Use null-or-empty pattern

src/main/org/apache/tools/ant/ArgumentProcessorRegistry.java

@@ -157,7 +157,7 @@ public class ArgumentProcessorRegistry {
             }
             BufferedReader rd = new BufferedReader(isr);
             String processorClassName = rd.readLine();
-            if (processorClassName != null && !"".equals(processorClassName)) {
+            if (processorClassName != null && !processorClassName.isEmpty()) {
                 return getProcessor(processorClassName);
             }
         } finally {

src/main/org/apache/tools/ant/ComponentHelper.java

@@ -1018,7 +1018,7 @@ public class ComponentHelper  {
         out.println("Action: Check that any custom tasks/types have been declared.");
         out.println("Action: Check that any <presetdef>/<macrodef>"
                 + " declarations have taken place.");
-        if (uri.length() > 0) {
+        if (!uri.isEmpty()) {
             final List<AntTypeDefinition> matches = findTypeMatches(uri);
             if (matches.isEmpty()) {
                 out.println("No types or tasks have been defined in this namespace yet");

src/main/org/apache/tools/ant/DirectoryScanner.java

@@ -1016,8 +1016,7 @@ public class DirectoryScanner
                         continue;
                     }
                     if (myfile.isDirectory()) {
-                        if (isIncluded(currentPath)
-                            && currentelement.length() > 0) {
+                        if (isIncluded(currentPath) && !currentelement.isEmpty()) {
                             accountForIncludedDir(currentPath, myfile, true);
                         }  else {
                             scandir(myfile, currentPath, true);
@@ -1200,7 +1199,7 @@ public class DirectoryScanner
     private void scandir(final File dir, final TokenizedPath path, final boolean fast,
                          String[] newFiles, final Deque<String> directoryNamesFollowed) {
         String vpath = path.toString();
-        if (vpath.length() > 0 && !vpath.endsWith(File.separator)) {
+        if (!vpath.isEmpty() && !vpath.endsWith(File.separator)) {
             vpath += File.separator;
         }
 

src/main/org/apache/tools/ant/IntrospectionHelper.java

@@ -458,7 +458,7 @@ public final class IntrospectionHelper {
         if (addText == null) {
             text = text.trim();
             // Element doesn't handle text content
-            if (text.length() == 0) {
+            if (text.isEmpty()) {
                 // Only whitespace - ignore
                 return;
             }
@@ -530,7 +530,7 @@ public final class IntrospectionHelper {
             parentUri = "";
         }
         NestedCreator nc = null;
-        if (uri.equals(parentUri) || uri.length() == 0) {
+        if (uri.equals(parentUri) || uri.isEmpty()) {
             nc = nestedCreators.get(name.toLowerCase(Locale.ENGLISH));
         }
         if (nc == null) {
@@ -741,10 +741,7 @@ public final class IntrospectionHelper {
             return false;
         }
         String uri = ProjectHelper.extractUriFromComponentName(elementName);
-        if (uri.equals(ProjectHelper.ANT_CORE_URI)) {
-            uri = "";
-        }
-        if ("".equals(uri)) {
+        if (uri.equals(ProjectHelper.ANT_CORE_URI) || uri.isEmpty()) {
             return true;
         }
         if (parentUri.equals(ProjectHelper.ANT_CORE_URI)) {
@@ -1058,7 +1055,7 @@ public final class IntrospectionHelper {
                 @Override
                 public void set(final Project p, final Object parent, final String value)
                         throws InvocationTargetException, IllegalAccessException {
-                    if (value.length() == 0) {
+                    if (value.isEmpty()) {
                         throw new BuildException("The value \"\" is not a "
                                 + "legal value for attribute \"" + attrName + "\"");
                     }

src/main/org/apache/tools/ant/Main.java

@@ -1217,7 +1217,7 @@ public class Main implements AntMain {
         }
 
         final String defaultTarget = project.getDefaultTarget();
-        if (defaultTarget != null && !"".equals(defaultTarget)) {
+        if (defaultTarget != null && defaultTarget.isEmpty()) {
             // shouldn't need to check but...
             project.log("Default target: " + defaultTarget);
         }

src/main/org/apache/tools/ant/NoBannerLogger.java

@@ -84,7 +84,7 @@ public class NoBannerLogger extends DefaultLogger {
 
         if (event.getPriority() > msgOutputLevel
             || null == event.getMessage()
-            || "".equals(event.getMessage().trim())) {
+            || event.getMessage().trim().isEmpty()) {
                 return;
         }
 

src/main/org/apache/tools/ant/ProjectHelper.java

@@ -494,7 +494,7 @@ public class ProjectHelper {
      * @return      The stringified form of the ns name
      */
     public static String genComponentName(String uri, String name) {
-        if (uri == null || "".equals(uri) || uri.equals(ANT_CORE_URI)) {
+        if (uri == null || uri.isEmpty() || uri.equals(ANT_CORE_URI)) {
             return name;
         }
         return uri + ":" + name;

src/main/org/apache/tools/ant/ProjectHelperRepository.java

@@ -197,7 +197,7 @@ public class ProjectHelperRepository {
             String helperClassName = rd.readLine();
             rd.close();
 
-            if (helperClassName != null && !"".equals(helperClassName)) {
+            if (helperClassName != null && !helperClassName.isEmpty()) {
                 return getHelperConstructor(helperClassName);
             }
         } catch (Exception e) {

src/main/org/apache/tools/ant/RuntimeConfigurable.java

@@ -391,7 +391,7 @@ public class RuntimeConfigurable implements Serializable {
      *        Should not be <code>null</code>.
      */
     public synchronized void addText(String data) {
-        if (data.length() == 0) {
+        if (data.isEmpty()) {
             return;
         }
         characters = (characters == null)

src/main/org/apache/tools/ant/XmlLogger.java

@@ -182,7 +182,7 @@ public class XmlLogger implements BuildLogger {
             outStream == null ? Files.newOutputStream(Paths.get(outFilename)) : outStream;
                 Writer out = new OutputStreamWriter(stream, "UTF8")) {
             out.write("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
-            if (xslUri.length() > 0) {
+            if (!xslUri.isEmpty()) {
                 out.write("<?xml-stylesheet type=\"text/xsl\" href=\"" + xslUri
                     + "\"?>\n\n");
             }

src/main/org/apache/tools/ant/filters/ClassConstants.java

@@ -88,13 +88,13 @@ public final class ClassConstants
     public int read() throws IOException {
         int ch = -1;
 
-        if (queuedData != null && queuedData.length() == 0) {
+        if (queuedData != null && queuedData.isEmpty()) {
             queuedData = null;
         }
 
         if (queuedData == null) {
             final String clazz = readFully();
-            if (clazz == null || clazz.length() == 0) {
+            if (clazz == null || clazz.isEmpty()) {
                 ch = -1;
             } else {
                 final byte[] bytes = clazz.getBytes(ResourceUtils.ISO_8859_1);
@@ -130,7 +130,7 @@ public final class ClassConstants
         } else {
             ch = queuedData.charAt(0);
             queuedData = queuedData.substring(1);
-            if (queuedData.length() == 0) {
+            if (queuedData.isEmpty()) {
                 queuedData = null;
             }
         }

src/main/org/apache/tools/ant/filters/HeadFilter.java

@@ -105,7 +105,7 @@ public final class HeadFilter extends BaseParamFilterReader
             setInitialized(true);
         }
 
-        while (line == null || line.length() == 0) {
+        while (line == null || line.isEmpty()) {
             line = lineTokenizer.getToken(in);
             if (line == null) {
                 return -1;

src/main/org/apache/tools/ant/filters/PrefixLines.java

@@ -86,14 +86,14 @@ public final class PrefixLines
 
         int ch = -1;
 
-        if (queuedData != null && queuedData.length() == 0) {
+        if (queuedData != null && queuedData.isEmpty()) {
             queuedData = null;
         }
 
         if (queuedData != null) {
             ch = queuedData.charAt(0);
             queuedData = queuedData.substring(1);
-            if (queuedData.length() == 0) {
+            if (queuedData.isEmpty()) {
                 queuedData = null;
             }
         } else {

src/main/org/apache/tools/ant/filters/ReplaceTokens.java

@@ -134,7 +134,7 @@ public final class ReplaceTokens
         }
 
         // is the read buffer empty?
-        if (readBuffer.length() == 0) {
+        if (readBuffer.isEmpty()) {
             int next = in.read();
             if (next == -1) {
                 return next; // end of stream. all buffers empty.
@@ -169,13 +169,13 @@ public final class ReplaceTokens
      * @return the first character from the read buffer or -1 if read buffer is empty.
      */
     private int getFirstCharacterFromReadBuffer() {
-        if (readBuffer.length() > 0) {
-            int chr = readBuffer.charAt(0);
-            readBuffer = readBuffer.substring(1);
-            return chr;
-        } else {
+        if (readBuffer.isEmpty()) {
             return -1;
         }
+
+        int chr = readBuffer.charAt(0);
+        readBuffer = readBuffer.substring(1);
+        return chr;
     }
 
     /**

src/main/org/apache/tools/ant/filters/SuffixLines.java

@@ -87,17 +87,11 @@ public final class SuffixLines
 
         int ch = -1;
 
-        if (queuedData != null && queuedData.length() == 0) {
+        if (queuedData != null && queuedData.isEmpty()) {
             queuedData = null;
         }
 
-        if (queuedData != null) {
-            ch = queuedData.charAt(0);
-            queuedData = queuedData.substring(1);
-            if (queuedData.length() == 0) {
-                queuedData = null;
-            }
-        } else {
+        if (queuedData == null) {
             queuedData = readLine();
             if (queuedData == null) {
                 ch = -1;
@@ -116,6 +110,12 @@ public final class SuffixLines
                 }
                 return read();
             }
+        } else {
+            ch = queuedData.charAt(0);
+            queuedData = queuedData.substring(1);
+            if (queuedData.isEmpty()) {
+                queuedData = null;
+            }
         }
         return ch;
     }

src/main/org/apache/tools/ant/filters/TailFilter.java

@@ -108,7 +108,7 @@ public final class TailFilter extends BaseParamFilterReader
             setInitialized(true);
         }
 
-        while (line == null || line.length() == 0) {
+        while (line == null || line.isEmpty()) {
             line = lineTokenizer.getToken(in);
             line = tailFilter(line);
             if (line == null) {

src/main/org/apache/tools/ant/filters/TokenFilter.java

@@ -105,7 +105,7 @@ public class TokenFilter extends BaseFilterReader
         if (tokenizer == null) {
             tokenizer = new LineTokenizer();
         }
-        while (line == null || line.length() == 0) {
+        while (line == null || line.isEmpty()) {
             line = tokenizer.getToken(in);
             if (line == null) {
                 return -1;
@@ -117,13 +117,11 @@ public class TokenFilter extends BaseFilterReader
                 }
             }
             linePos = 0;
-            if (line != null) {
-                if (tokenizer.getPostToken().length() != 0) {
-                    if (delimOutput != null) {
-                        line += delimOutput;
-                    } else {
-                        line += tokenizer.getPostToken();
-                    }
+            if (line != null && !tokenizer.getPostToken().isEmpty()) {
+                if (delimOutput != null) {
+                    line += delimOutput;
+                } else {
+                    line += tokenizer.getPostToken();
                 }
             }
         }
@@ -593,7 +591,7 @@ public class TokenFilter extends BaseFilterReader
          * @return the trimmed line
          */
         public String filter(String line) {
-            if (line.trim().length() == 0) {
+            if (line.trim().isEmpty()) {
                 return null;
             }
             return line;

src/main/org/apache/tools/ant/helper/ProjectHelper2.java

@@ -467,7 +467,7 @@ public class ProjectHelper2 extends ProjectHelper {
             throws SAXParseException {
             String s = new String(buf, start, count).trim();
 
-            if (s.length() > 0) {
+            if (!s.isEmpty()) {
                 throw new SAXParseException("Unexpected text \"" + s + "\"", context.getLocator());
             }
         }
@@ -984,7 +984,7 @@ public class ProjectHelper2 extends ProjectHelper {
                                          target.getLocation());
             }
             Hashtable<String, Target> projectTargets = project.getTargets();
-            boolean   usedTarget = false;
+            boolean usedTarget = false;
             // If the name has not already been defined define it
             if (projectTargets.containsKey(name)) {
                 project.log("Already defined in main or a previous import, ignore " + name,
@@ -996,7 +996,7 @@ public class ProjectHelper2 extends ProjectHelper {
                 usedTarget = true;
             }
 
-            if (depends.length() > 0) {
+            if (!depends.isEmpty()) {
                 if (!isInIncludeMode) {
                     target.setDepends(depends);
                 } else {
@@ -1052,7 +1052,7 @@ public class ProjectHelper2 extends ProjectHelper {
 
         private String getTargetPrefix(AntXMLContext context) {
             String configuredValue = getCurrentTargetPrefix();
-            if (configuredValue != null && configuredValue.length() == 0) {
+            if (configuredValue != null && configuredValue.isEmpty()) {
                 configuredValue = null;
             }
             if (configuredValue != null) {

src/main/org/apache/tools/ant/helper/ProjectHelperImpl.java

@@ -246,7 +246,7 @@ public class ProjectHelperImpl extends ProjectHelper {
         public void characters(char[] buf, int start, int count) throws SAXParseException {
             String s = new String(buf, start, count).trim();
 
-            if (s.length() > 0) {
+            if (!s.isEmpty()) {
                 throw new SAXParseException("Unexpected text \"" + s + "\"", helperImpl.locator);
             }
         }
@@ -579,7 +579,7 @@ public class ProjectHelperImpl extends ProjectHelper {
 
             // take care of dependencies
 
-            if (depends.length() > 0) {
+            if (!depends.isEmpty()) {
                 target.setDepends(depends);
             }
         }

src/main/org/apache/tools/ant/listener/MailLogger.java

@@ -370,15 +370,15 @@ public class MailLogger extends DefaultLogger {
 
         mailMessage.setSubject(values.subject());
 
-        if (values.charset().length() > 0) {
+        if (values.charset().isEmpty()) {
+            mailMessage.setHeader("Content-Type", values.mimeType());
+        } else {
             mailMessage.setHeader("Content-Type", values.mimeType()
                                   + "; charset=\"" + values.charset() + "\"");
-        } else {
-            mailMessage.setHeader("Content-Type", values.mimeType());
         }
 
         PrintStream ps = mailMessage.getPrintStream();
-        ps.println(values.body().length() > 0 ? values.body() : message);
+        ps.println(values.body().isEmpty() ? message : values.body());
 
         mailMessage.sendAndClose();
     }
@@ -408,10 +408,10 @@ public class MailLogger extends DefaultLogger {
         mailer.setSSL(values.ssl());
         mailer.setEnableStartTLS(values.starttls());
         Message mymessage =
-            new Message(values.body().length() > 0 ? values.body() : message);
+            new Message(!values.body().isEmpty() ? values.body() : message);
         mymessage.setProject(project);
         mymessage.setMimeType(values.mimeType());
-        if (values.charset().length() > 0) {
+        if (!values.charset().isEmpty()) {
             mymessage.setCharset(values.charset());
         }
         mailer.setMessage(mymessage);

src/main/org/apache/tools/ant/taskdefs/Ant.java

@@ -488,7 +488,7 @@ public class Ant extends Task {
         Set<String> set = new HashSet<>();
         for (int i = properties.size() - 1; i >= 0; --i) {
             Property p = properties.get(i);
-            if (p.getName() != null && !"".equals(p.getName())) {
+            if (p.getName() != null && !p.getName().isEmpty()) {
                 if (set.contains(p.getName())) {
                     properties.remove(i);
                 } else {

src/main/org/apache/tools/ant/taskdefs/Exit.java

@@ -141,12 +141,10 @@ public class Exit extends Task {
             if (message != null && !message.trim().isEmpty()) {
                 text = message.trim();
             } else {
-                if (ifCondition != null && !"".equals(ifCondition)
-                    && testIfCondition()) {
+                if (!isNullOrEmpty(ifCondition) && testIfCondition()) {
                     text = "if=" + ifCondition;
                 }
-                if (unlessCondition != null && !"".equals(unlessCondition)
-                    && testUnlessCondition()) {
+                if (!isNullOrEmpty(unlessCondition) && testUnlessCondition()) {
                     if (text == null) {
                         text = "";
                     } else {
@@ -166,6 +164,10 @@ public class Exit extends Task {
         }
     }
 
+    private boolean isNullOrEmpty(Object value) {
+        return value == null || "".equals(value);
+    }
+
     /**
      * Set a multiline message.
      * @param msg the message to display

src/main/org/apache/tools/ant/taskdefs/Get.java

@@ -273,7 +273,7 @@ public class Get extends Task {
      */
     private void checkAttributes() {
 
-        if (userAgent == null || userAgent.trim().length() == 0) {
+        if (userAgent == null || userAgent.trim().isEmpty()) {
             throw new BuildException("userAgent may not be null or empty");
         }
 

src/main/org/apache/tools/ant/taskdefs/Javadoc.java

@@ -1055,7 +1055,7 @@ public class Javadoc extends Task {
         final String linkOfflineError = "The linkoffline attribute must include"
             + " a URL and a package-list file location separated by a"
             + " space";
-        if (src.trim().length() == 0) {
+        if (src.trim().isEmpty()) {
             throw new BuildException(linkOfflineError);
         }
         final StringTokenizer tok = new StringTokenizer(src, " ", false);

src/main/org/apache/tools/ant/taskdefs/KeySubst.java

@@ -72,7 +72,7 @@ public class KeySubst extends Task {
             String newline = null;
             line = br.readLine();
             while (line != null) {
-                if (line.length() == 0) {
+                if (line.isEmpty()) {
                     bw.newLine();
                 } else {
                     newline = KeySubst.replace(line, replacements);
@@ -128,7 +128,7 @@ public class KeySubst extends Task {
      * @param keys a <code>String</code> value
      */
     public void setKeys(String keys) {
-        if (keys != null && keys.length() > 0) {
+        if (keys != null && !keys.isEmpty()) {
             StringTokenizer tok =
             new StringTokenizer(keys, this.sep, false);
             while (tok.hasMoreTokens()) {

src/main/org/apache/tools/ant/taskdefs/MacroDef.java

@@ -237,7 +237,7 @@ public class MacroDef extends AntlibDefinition  {
      * @return true if the name consists of valid name characters
      */
     private static boolean isValidName(String name) {
-        if (name.length() == 0) {
+        if (name.isEmpty()) {
             return false;
         }
         for (int i = 0; i < name.length(); ++i) {
@@ -724,9 +724,9 @@ public class MacroDef extends AntlibDefinition  {
         } else if (!text.equals(other.text)) {
             return false;
         }
-        if (getURI() == null || "".equals(getURI())
+        if (getURI() == null || getURI().isEmpty()
                 || getURI().equals(ProjectHelper.ANT_CORE_URI)) {
-            if (other.getURI() != null && !"".equals(other.getURI())
+            if (other.getURI() != null && !other.getURI().isEmpty()
                     && !other.getURI().equals(ProjectHelper.ANT_CORE_URI)) {
                 return false;
             }

src/main/org/apache/tools/ant/taskdefs/MatchingTask.java

@@ -136,7 +136,7 @@ public abstract class MatchingTask extends Task implements SelectorContainer {
             StringTokenizer tok = new StringTokenizer(itemString, ", ");
             while (tok.hasMoreTokens()) {
                 String pattern = tok.nextToken().trim();
-                if (pattern.length() > 0) {
+                if (!pattern.isEmpty()) {
                     createInclude().setName(pattern + "/**");
                 }
             }

src/main/org/apache/tools/ant/taskdefs/SubAnt.java

@@ -569,7 +569,7 @@ public class SubAnt extends Task {
     private Ant createAntTask(File directory) {
         Ant antTask = new Ant(this);
         antTask.init();
-        if (subTarget != null && subTarget.length() > 0) {
+        if (subTarget != null && !subTarget.isEmpty()) {
             antTask.setTarget(subTarget);
         }
 

src/main/org/apache/tools/ant/taskdefs/Tar.java

@@ -399,11 +399,9 @@ public class Tar extends MatchingTask {
 
         if (tarFileSet != null) {
             final String fullpath = tarFileSet.getFullpath(this.getProject());
-            if (fullpath.length() > 0) {
-                vPath = fullpath;
-            } else {
+            if (fullpath.isEmpty()) {
                 // don't add "" to the archive
-                if (vPath.length() <= 0) {
+                if (vPath.isEmpty()) {
                     return;
                 }
 
@@ -413,6 +411,8 @@ public class Tar extends MatchingTask {
                     prefix += "/";
                 }
                 vPath = prefix + vPath;
+            } else {
+                vPath = fullpath;
             }
 
             preserveLeadingSlashes = tarFileSet.getPreserveLeadingSlashes();

src/main/org/apache/tools/ant/taskdefs/Tstamp.java

@@ -144,7 +144,7 @@ public class Tstamp extends Task {
      */
     protected Optional<Date> getNow(String propertyName, Function<String, Date> map, BiFunction<String, String, String> log) {
         String property = getProject().getProperty(propertyName);
-        if (property != null && property.length() > 0) {
+        if (property != null && !property.isEmpty()) {
             try {
                 return Optional.ofNullable(map.apply(property));
             } catch (Exception e) {

src/main/org/apache/tools/ant/taskdefs/XmlProperty.java

@@ -290,7 +290,7 @@ public class XmlProperty extends Task {
         // Set the prefix for this node to include its tag name.
         String nodePrefix = prefix;
         if (node.getNodeType() != Node.TEXT_NODE) {
-            if (prefix.trim().length() > 0) {
+            if (!prefix.trim().isEmpty()) {
                 nodePrefix += ".";
             }
             nodePrefix += node.getNodeName();

src/main/org/apache/tools/ant/taskdefs/Zip.java

@@ -936,12 +936,12 @@ public class Zip extends MatchingTask {
             fileMode = zfs.getFileMode(getProject());
         }
 
-        if (prefix.length() > 0 && fullpath.length() > 0) {
+        if (!prefix.isEmpty() && !fullpath.isEmpty()) {
             throw new BuildException(
                 "Both prefix and fullpath attributes must not be set on the same fileset.");
         }
 
-        if (resources.length != 1 && fullpath.length() > 0) {
+        if (resources.length != 1 && !fullpath.isEmpty()) {
             throw new BuildException(
                 "fullpath attribute may only be specified for filesets that specify a single file.");
         }

src/main/org/apache/tools/ant/taskdefs/condition/IsReachable.java

@@ -125,10 +125,10 @@ public class IsReachable extends ProjectComponent implements Condition {
      *
      * @param string param to check
      *
-     * @return true if it is empty
+     * @return true if it is isNullOrEmpty
      */
-    private boolean empty(final String string) {
-        return string == null || string.length() == 0;
+    private boolean isNullOrEmpty(final String string) {
+        return string == null || string.isEmpty();
     }
 
     /**
@@ -141,22 +141,22 @@ public class IsReachable extends ProjectComponent implements Condition {
      */
     @Override
     public boolean eval() throws BuildException {
-        if (empty(host) && empty(url)) {
+        if (isNullOrEmpty(host) && isNullOrEmpty(url)) {
             throw new BuildException(ERROR_NO_HOSTNAME);
         }
         if (timeout < 0) {
             throw new BuildException(ERROR_BAD_TIMEOUT);
         }
         String target = host;
-        if (!empty(url)) {
-            if (!empty(host)) {
+        if (!isNullOrEmpty(url)) {
+            if (!isNullOrEmpty(host)) {
                 throw new BuildException(ERROR_BOTH_TARGETS);
             }
             try {
                 //get the host of a url
                 final URL realURL = new URL(url);
                 target = realURL.getHost();
-                if (empty(target)) {
+                if (isNullOrEmpty(target)) {
                     throw new BuildException(ERROR_NO_HOST_IN_URL + url);
                 }
             } catch (final MalformedURLException e) {

src/main/org/apache/tools/ant/taskdefs/condition/ResourceContains.java

@@ -135,7 +135,7 @@ public class ResourceContains implements Condition {
     public synchronized boolean eval() throws BuildException {
         validate();
 
-        if (substring.length() == 0) {
+        if (substring.isEmpty()) {
             if (getProject() != null) {
                 getProject().log("Substring is empty; returning true",
                                  Project.MSG_VERBOSE);

src/main/org/apache/tools/ant/taskdefs/optional/EchoProperties.java

@@ -184,7 +184,7 @@ public class EchoProperties extends Task {
      * @param  prefix  The new prefix value
      */
     public void setPrefix(String prefix) {
-        if (prefix != null && prefix.length() != 0) {
+        if (prefix != null && !prefix.isEmpty()) {
             this.prefix = prefix;
             PropertySet ps = new PropertySet();
             ps.setProject(getProject());

src/main/org/apache/tools/ant/taskdefs/optional/ReplaceRegExp.java

@@ -365,7 +365,7 @@ public class ReplaceRegExp extends Task {
                     log("Replacing pattern '" + regex.getPattern(getProject())
                         + "' with '" + subs.getExpression(getProject())
                         + "' in '" + f.getPath() + "'" + (byline ? " by line" : "")
-                        + (flags.length() > 0 ? " with flags: '" + flags + "'" : "")
+                        + (flags.isEmpty() ? "" : " with flags: '" + flags + "'")
                         + ".", Project.MSG_VERBOSE);
 
                     if (byline) {

src/main/org/apache/tools/ant/taskdefs/optional/ejb/GenericDeploymentTool.java

@@ -417,7 +417,7 @@ public class GenericDeploymentTool implements EJBDeploymentTool {
 
             // Lastly create File object for the Jar files. If we are using
             // a flat destination dir, then we need to redefine baseName!
-            if (config.flatDestDir && baseName.length() != 0) {
+            if (config.flatDestDir && !baseName.isEmpty()) {
                 int startName = baseName.lastIndexOf(File.separator);
                 if (startName == -1) {
                     startName = 0;

src/main/org/apache/tools/ant/taskdefs/optional/ejb/WebsphereDeploymentTool.java

@@ -553,7 +553,7 @@ public class WebsphereDeploymentTool extends GenericDeploymentTool {
                 javaTask.createArg().setValue(destJar.getPath());
                 javaTask.createArg().setLine(getOptions());
                 if (getCombinedClasspath() != null
-                    && getCombinedClasspath().toString().length() > 0) {
+                    && !getCombinedClasspath().toString().isEmpty()) {
                     javaTask.createArg().setValue("-cp");
                     javaTask.createArg().setValue(getCombinedClasspath().toString());
                 }

src/main/org/apache/tools/ant/taskdefs/optional/i18n/Translate.java

@@ -365,12 +365,9 @@ public class Translate extends MatchingTask {
                                    bundleCountry,
                                    bundleVariant);
 
-        String language = locale.getLanguage().length() > 0
-            ? "_" + locale.getLanguage() : "";
-        String country = locale.getCountry().length() > 0
-            ? "_" + locale.getCountry() : "";
-        String variant = locale.getVariant().length() > 0
-            ? "_" + locale.getVariant() : "";
+        String language = locale.getLanguage().isEmpty() ? "" : "_" + locale.getLanguage();
+        String country = locale.getCountry().isEmpty() ? "" : "_" + locale.getCountry();
+        String variant = locale.getVariant().isEmpty() ? "" : "_" + locale.getVariant();
 
         processBundle(bundle + language + country + variant, BUNDLE_SPECIFIED_LANGUAGE_COUNTRY_VARIANT, false);
         processBundle(bundle + language + country, BUNDLE_SPECIFIED_LANGUAGE_COUNTRY, false);
@@ -381,12 +378,9 @@ public class Translate extends MatchingTask {
         //using default file encoding scheme.
         locale = Locale.getDefault();
 
-        language = locale.getLanguage().length() > 0
-            ? "_" + locale.getLanguage() : "";
-        country = locale.getCountry().length() > 0
-            ? "_" + locale.getCountry() : "";
-        variant = locale.getVariant().length() > 0
-            ? "_" + locale.getVariant() : "";
+        language = locale.getLanguage().isEmpty() ? "" : "_" + locale.getLanguage();
+        country = locale.getCountry().isEmpty() ? "" : "_" + locale.getCountry();
+        variant = locale.getVariant().isEmpty() ? "" : "_" + locale.getVariant();
         bundleEncoding = System.getProperty("file.encoding");
 
         processBundle(bundle + language + country + variant, BUNDLE_DEFAULT_LANGUAGE_COUNTRY_VARIANT, false);
@@ -456,7 +450,7 @@ public class Translate extends MatchingTask {
                                 break;
                             }
                         }
-                        if (key.length() > 0) {
+                        if (!key.isEmpty()) {
                             //Has key already been loaded into resourceMap?
                             resourceMap.putIfAbsent(key, value);
                         }

src/main/org/apache/tools/ant/taskdefs/optional/jdepend/JDependTask.java

@@ -556,7 +556,7 @@ public class JDependTask extends Task {
 
         // not sure whether this test is needed but cost nothing to put.
         // hope it will be reviewed by anybody competent
-        if (getClasspath().toString().length() > 0) {
+        if (!getClasspath().toString().isEmpty()) {
             createJvmarg(commandline).setValue("-classpath");
             createJvmarg(commandline).setValue(getClasspath().toString());
         }

src/main/org/apache/tools/ant/taskdefs/optional/jsp/WLJspc.java

@@ -174,7 +174,7 @@ public class WLJspc extends MatchingTask {
             File jspFile = new File(filename);
             args[j] = "-package";
             String parents = jspFile.getParent();
-            if (parents == null || "".equals(parents)) {
+            if (parents == null || parents.isEmpty()) {
                 args[j + 1] = destinationPackage;
             } else {
                 parents = this.replaceString(parents, File.separator, "_.");
@@ -265,7 +265,7 @@ public class WLJspc extends MatchingTask {
             String parents = jspFile.getParent();
 
             String pack;
-            if (parents == null || "".equals(parents)) {
+            if (parents == null || parents.isEmpty()) {
                 pack = pathToPackage;
             } else {
                 parents =  this.replaceString(parents, File.separator, "_/");

src/main/org/apache/tools/ant/taskdefs/optional/jsp/compilers/DefaultJspCompilerAdapter.java

@@ -87,7 +87,7 @@ public abstract class DefaultJspCompilerAdapter
      * @param  argument  The argument
      */
     protected void addArg(CommandlineJava cmd, String argument) {
-        if (argument != null && argument.length() != 0) {
+        if (argument != null && !argument.isEmpty()) {
            cmd.createArgument().setValue(argument);
         }
     }

src/main/org/apache/tools/ant/taskdefs/optional/junit/BriefJUnitResultFormatter.java

@@ -152,7 +152,7 @@ public class BriefJUnitResultFormatter implements JUnitResultFormatter, IgnoredT
         sb.append(StringUtils.LINE_SEP);
 
         // append the err and output streams to the log
-        if (systemOutput != null && systemOutput.length() > 0) {
+        if (systemOutput != null && !systemOutput.isEmpty()) {
             sb.append("------------- Standard Output ---------------")
                     .append(StringUtils.LINE_SEP)
                     .append(systemOutput)
@@ -160,7 +160,7 @@ public class BriefJUnitResultFormatter implements JUnitResultFormatter, IgnoredT
                     .append(StringUtils.LINE_SEP);
         }
 
-        if (systemError != null && systemError.length() > 0) {
+        if (systemError != null && !systemError.isEmpty()) {
             sb.append("------------- Standard Error -----------------")
                     .append(StringUtils.LINE_SEP)
                     .append(systemError)

src/main/org/apache/tools/ant/taskdefs/optional/junit/JUnit4TestMethodAdapter.java

@@ -67,7 +67,7 @@ public class JUnit4TestMethodAdapter implements Test {
             if (methodNames[i] == null) {
                 throw new IllegalArgumentException("method name #" + i + " is <null>");
             }
-            if (methodNames[i].length() == 0) {
+            if (methodNames[i].isEmpty()) {
                 throw new IllegalArgumentException("method name #" + i + " is empty");
             }
         }

src/main/org/apache/tools/ant/taskdefs/optional/junit/JUnitVersionHelper.java

@@ -155,7 +155,7 @@ public class JUnitVersionHelper {
                 if (annotation != null) {
                     Method valueMethod = annotation.annotationType().getMethod("value");
                     String value = (String) valueMethod.invoke(annotation);
-                    if (value != null && value.length() > 0) {
+                    if (value != null && !value.isEmpty()) {
                         message = value;
                     }
                 }

src/main/org/apache/tools/ant/taskdefs/optional/junit/PlainJUnitResultFormatter.java

@@ -127,7 +127,7 @@ public class PlainJUnitResultFormatter implements JUnitResultFormatter, IgnoredT
                     nf.format(suite.getRunTime() / ONE_SECOND)));
 
             // write the err and output streams to the log
-            if (systemOutput != null && systemOutput.length() > 0) {
+            if (systemOutput != null && !systemOutput.isEmpty()) {
                 write("------------- Standard Output ---------------");
                 write(StringUtils.LINE_SEP);
                 write(systemOutput);
@@ -135,7 +135,7 @@ public class PlainJUnitResultFormatter implements JUnitResultFormatter, IgnoredT
                 write(StringUtils.LINE_SEP);
             }
 
-            if (systemError != null && systemError.length() > 0) {
+            if (systemError != null && !systemError.isEmpty()) {
                 write("------------- Standard Error -----------------");
                 write(StringUtils.LINE_SEP);
                 write(systemError);

src/main/org/apache/tools/ant/taskdefs/optional/junit/SummaryJUnitResultFormatter.java

@@ -190,11 +190,11 @@ public class SummaryJUnitResultFormatter
         sb.append(System.lineSeparator());
 
         if (withOutAndErr) {
-            if (systemOutput != null && systemOutput.length() > 0) {
+            if (systemOutput != null && !systemOutput.isEmpty()) {
                 sb.append(String.format("Output:%n%s%n", systemOutput));
             }
 
-            if (systemError != null && systemError.length() > 0) {
+            if (systemError != null && !systemError.isEmpty()) {
                 sb.append(String.format("Output:%n%s%n", systemError));
             }
         }

src/main/org/apache/tools/ant/taskdefs/optional/junit/XMLJUnitResultFormatter.java

@@ -313,7 +313,7 @@ public class XMLJUnitResultFormatter implements JUnitResultFormatter, XMLConstan
         currentTest.appendChild(nested);
 
         final String message = t.getMessage();
-        if (message != null && message.length() > 0) {
+        if (message != null && !message.isEmpty()) {
             nested.setAttribute(ATTR_MESSAGE, t.getMessage());
         }
         nested.setAttribute(ATTR_TYPE, t.getClass().getName());

src/main/org/apache/tools/ant/taskdefs/optional/net/FTP.java

@@ -467,22 +467,19 @@ public class FTP extends Task implements FTPTaskConfig {
                 }
 
                 if (myfile.isDirectory()) {
-                    if (isIncluded(currentelement)
-                        && currentelement.length() > 0) {
+                    if (isIncluded(currentelement) && !currentelement.isEmpty()) {
                         accountForIncludedDir(currentelement, myfile, true);
-                    }  else {
-                        if (currentelement.length() > 0
+                    } else {
+                        if (!currentelement.isEmpty()
                                 && currentelement.charAt(currentelement.length() - 1)
                                 != File.separatorChar) {
                             currentelement += File.separatorChar;
                         }
                         scandir(myfile.getAbsolutePath(), currentelement, true);
                     }
-                } else if (isCaseSensitive
-                    && originalpattern.equals(currentelement)) {
+                } else if (isCaseSensitive && originalpattern.equals(currentelement)) {
                     accountForIncludedFile(currentelement);
-                } else if (!isCaseSensitive && originalpattern
-                    .equalsIgnoreCase(currentelement)) {
+                } else if (!isCaseSensitive && originalpattern.equalsIgnoreCase(currentelement)) {
                     accountForIncludedFile(currentelement);
                 }
             }
@@ -1490,7 +1487,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setSystemTypeKey(FTPSystemType systemKey) {
-        if (systemKey != null && !"".equals(systemKey.getValue())) {
+        if (systemKey != null && !systemKey.getValue().isEmpty()) {
             this.systemTypeKey = systemKey;
             configurationHasBeenSet();
         }
@@ -1503,7 +1500,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setDefaultDateFormatConfig(String defaultDateFormat) {
-        if (defaultDateFormat != null && !"".equals(defaultDateFormat)) {
+        if (defaultDateFormat != null && !defaultDateFormat.isEmpty()) {
             this.defaultDateFormatConfig = defaultDateFormat;
             configurationHasBeenSet();
         }
@@ -1516,7 +1513,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setRecentDateFormatConfig(String recentDateFormat) {
-        if (recentDateFormat != null && !"".equals(recentDateFormat)) {
+        if (recentDateFormat != null && !recentDateFormat.isEmpty()) {
             this.recentDateFormatConfig = recentDateFormat;
             configurationHasBeenSet();
         }
@@ -1542,7 +1539,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setServerTimeZoneConfig(String serverTimeZoneId) {
-        if (serverTimeZoneId != null && !"".equals(serverTimeZoneId)) {
+        if (serverTimeZoneId != null && !serverTimeZoneId.isEmpty()) {
             this.serverTimeZoneConfig = serverTimeZoneId;
             configurationHasBeenSet();
         }
@@ -1556,7 +1553,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setShortMonthNamesConfig(String shortMonthNames) {
-        if (shortMonthNames != null && !"".equals(shortMonthNames)) {
+        if (shortMonthNames != null && !shortMonthNames.isEmpty()) {
             this.shortMonthNamesConfig = shortMonthNames;
             configurationHasBeenSet();
         }
@@ -1652,7 +1649,7 @@ public class FTP extends Task implements FTPTaskConfig {
      * @param timestampGranularity The timestampGranularity to set.
      */
     public void setTimestampGranularity(Granularity timestampGranularity) {
-        if (null == timestampGranularity || "".equals(timestampGranularity.getValue())) {
+        if (null == timestampGranularity || timestampGranularity.getValue().isEmpty()) {
             return;
         }
         this.timestampGranularity = timestampGranularity;

src/main/org/apache/tools/ant/taskdefs/optional/net/FTPConfigurator.java

@@ -43,7 +43,7 @@ class FTPConfigurator {
         task.log("custom configuration", Project.MSG_VERBOSE);
         FTPClientConfig config;
         String systemTypeKey = task.getSystemTypeKey();
-        if (systemTypeKey != null && !"".equals(systemTypeKey)) {
+        if (systemTypeKey != null && !systemTypeKey.isEmpty()) {
             config = new FTPClientConfig(systemTypeKey);
             task.log("custom config: system key = "
                     + systemTypeKey, Project.MSG_VERBOSE);
@@ -69,7 +69,7 @@ class FTPConfigurator {
 
         String serverLanguageCodeConfig = task.getServerLanguageCodeConfig();
         if (serverLanguageCodeConfig != null) {
-            if (!"".equals(serverLanguageCodeConfig)
+            if (!serverLanguageCodeConfig.isEmpty()
                 && !FTPClientConfig.getSupportedLanguageCodes()
                 .contains(serverLanguageCodeConfig)) {
                 throw new BuildException("unsupported language code" +

src/main/org/apache/tools/ant/taskdefs/optional/net/FTPTask.java

@@ -504,7 +504,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setSystemTypeKey(FTPSystemType systemKey) {
-        if (systemKey != null && !"".equals(systemKey.getValue())) {
+        if (systemKey != null && !systemKey.getValue().isEmpty()) {
             this.systemTypeKey = systemKey;
             configurationHasBeenSet();
         }
@@ -517,7 +517,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setDefaultDateFormatConfig(String defaultDateFormat) {
-        if (defaultDateFormat != null && !"".equals(defaultDateFormat)) {
+        if (defaultDateFormat != null && !defaultDateFormat.isEmpty()) {
             this.defaultDateFormatConfig = defaultDateFormat;
             configurationHasBeenSet();
         }
@@ -530,7 +530,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setRecentDateFormatConfig(String recentDateFormat) {
-        if (recentDateFormat != null && !"".equals(recentDateFormat)) {
+        if (recentDateFormat != null && recentDateFormat.isEmpty()) {
             this.recentDateFormatConfig = recentDateFormat;
             configurationHasBeenSet();
         }
@@ -556,7 +556,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setServerTimeZoneConfig(String serverTimeZoneId) {
-        if (serverTimeZoneId != null && !"".equals(serverTimeZoneId)) {
+        if (serverTimeZoneId != null && serverTimeZoneId.isEmpty()) {
             this.serverTimeZoneConfig = serverTimeZoneId;
             configurationHasBeenSet();
         }
@@ -570,7 +570,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @see org.apache.commons.net.ftp.FTPClientConfig
      */
     public void setShortMonthNamesConfig(String shortMonthNames) {
-        if (shortMonthNames != null && !"".equals(shortMonthNames)) {
+        if (shortMonthNames != null && !shortMonthNames.isEmpty()) {
             this.shortMonthNamesConfig = shortMonthNames;
             configurationHasBeenSet();
         }
@@ -671,7 +671,7 @@ public class FTPTask extends Task implements FTPTaskConfig {
      * @param timestampGranularity The timestampGranularity to set.
      */
     public void setTimestampGranularity(Granularity timestampGranularity) {
-        if (null == timestampGranularity || "".equals(timestampGranularity.getValue())) {
+        if (null == timestampGranularity || timestampGranularity.getValue().isEmpty()) {
             return;
         }
         this.timestampGranularity = timestampGranularity;

src/main/org/apache/tools/ant/taskdefs/optional/net/FTPTaskMirrorImpl.java

@@ -359,12 +359,10 @@ public class FTPTaskMirrorImpl implements FTPTaskMirror {
                 }
 
                 if (myfile.isDirectory()) {
-                    if (isIncluded(currentelement)
-                        && currentelement.length() > 0) {
+                    if (isIncluded(currentelement) && !currentelement.isEmpty()) {
                         accountForIncludedDir(currentelement, myfile, true);
-                    }  else {
-                        if (currentelement.length() > 0
-                                && currentelement.charAt(currentelement.length() - 1)
+                    } else {
+                        if (!currentelement.isEmpty() && currentelement.charAt(currentelement.length() - 1)
                                 != File.separatorChar) {
                             currentelement += File.separatorChar;
                         }

src/main/org/apache/tools/ant/taskdefs/optional/net/SetProxy.java

@@ -181,7 +181,7 @@ public class SetProxy extends Task {
         Properties sysprops = System.getProperties();
         if (proxyHost != null) {
             settingsChanged = true;
-            if (proxyHost.length() != 0) {
+            if (!proxyHost.isEmpty()) {
                 traceSettingInfo();
                 enablingProxy = true;
                 sysprops.put(ProxySetup.HTTP_PROXY_HOST, proxyHost);
@@ -216,7 +216,7 @@ public class SetProxy extends Task {
         //socks
         if (socksProxyHost != null) {
             settingsChanged = true;
-            if (socksProxyHost.length() != 0) {
+            if (!socksProxyHost.isEmpty()) {
                 enablingProxy = true;
                 sysprops.put(ProxySetup.SOCKS_PROXY_HOST, socksProxyHost);
                 sysprops.put(ProxySetup.SOCKS_PROXY_PORT, Integer.toString(socksProxyPort));

src/main/org/apache/tools/ant/taskdefs/optional/pvcs/Pvcs.java

@@ -243,7 +243,7 @@ public class Pvcs extends Task {
             commandLine.clearArgs();
             commandLine.setExecutable(getExecutable(GET_EXE));
 
-            if (getConfig() != null && getConfig().length() > 0) {
+            if (getConfig() != null && !getConfig().isEmpty()) {
                 commandLine.createArgument().setValue("-c" + getConfig());
             }
 

src/main/org/apache/tools/ant/taskdefs/optional/splash/SplashTask.java

@@ -182,8 +182,8 @@ public class SplashTask extends Task {
                 sp.setProxyPassword(password);
                 sp.applyWebProxySettings();
 
-                if (useProxy && (proxy != null && proxy.length() > 0)
-                    && (port != null && port.length() > 0)) {
+                if (useProxy && (proxy != null && !proxy.isEmpty())
+                    && (port != null && !port.isEmpty())) {
 
                     log("Using proxied Connection",  Project.MSG_DEBUG);
                     System.getProperties().put("http.proxySet", "true");
@@ -191,7 +191,7 @@ public class SplashTask extends Task {
                     URL url = new URL(imgurl);
 
                     conn = url.openConnection();
-                    if (user != null && user.length() > 0) {
+                    if (user != null && !user.isEmpty()) {
                         // converted from sun internal classes to
                         // new Base64Converter
                         // utility class extracted from Get task

src/main/org/apache/tools/ant/taskdefs/optional/ssh/SSHSession.java

@@ -85,7 +85,7 @@ public class SSHSession extends SSHBase {
      */
     public void setLocaltunnels(final String tunnels) {
         for (String tunnelSpec : tunnels.split(", ")) {
-            if (tunnelSpec.length() > 0) {
+            if (!tunnelSpec.isEmpty()) {
                 final String[] spec = tunnelSpec.split(":", 3);
                 final int lport = Integer.parseInt(spec[0]);
                 final String rhost = spec[1];
@@ -107,7 +107,7 @@ public class SSHSession extends SSHBase {
      */
     public void setRemotetunnels(final String tunnels) {
         for (String tunnelSpec : tunnels.split(", ")) {
-            if (tunnelSpec.length() > 0) {
+            if (!tunnelSpec.isEmpty()) {
                 final String[] spec = tunnelSpec.split(":", 3);
                 final int rport = Integer.parseInt(spec[0]);
                 final String lhost = spec[1];

src/main/org/apache/tools/ant/taskdefs/optional/vss/MSVSS.java

@@ -417,7 +417,7 @@ public abstract class MSVSS extends Task implements MSVSSConstants {
      */
     protected String getLabel() {
         String shortLabel = "";
-        if (label != null && label.length() > 0) {
+        if (label != null && !label.isEmpty()) {
                 shortLabel = FLAG_LABEL + getShortLabel();
         }
         return shortLabel;

src/main/org/apache/tools/ant/taskdefs/rmic/RmicAdapterFactory.java

@@ -95,7 +95,7 @@ public final class RmicAdapterFactory {
                                       Path classpath)
         throws BuildException {
         //handle default specially by choosing the sun or kaffe compiler
-        if (DEFAULT_COMPILER.equalsIgnoreCase(rmicType) || rmicType.length() == 0) {
+        if (DEFAULT_COMPILER.equalsIgnoreCase(rmicType) || rmicType.isEmpty()) {
             if (KaffeRmic.isAvailable()) {
                 rmicType = KaffeRmic.COMPILER_NAME;
             } else if (JavaEnvUtils.isAtLeastJavaVersion(JavaEnvUtils.JAVA_9)) {

src/main/org/apache/tools/ant/types/ArchiveScanner.java

@@ -256,7 +256,7 @@ public abstract class ArchiveScanner extends DirectoryScanner {
      */
     public boolean match(String path) {
         String vpath = path;
-        if (path.length() > 0) {
+        if (!path.isEmpty()) {
             vpath = path.replace('/', File.separatorChar).
                 replace('\\', File.separatorChar);
             if (vpath.charAt(0) == File.separatorChar) {

src/main/org/apache/tools/ant/types/Commandline.java

@@ -183,8 +183,7 @@ public class Commandline implements Cloneable {
          * @return an array of strings.
          */
         public String[] getParts() {
-            if (parts == null || parts.length == 0
-                    || (prefix.length() == 0 && suffix.length() == 0)) {
+            if (parts == null || parts.length == 0 || (prefix.isEmpty() && suffix.isEmpty())) {
                 return parts;
             }
             String[] fullParts = new String[parts.length];
@@ -327,7 +326,7 @@ public class Commandline implements Cloneable {
      * @since Ant 1.9.7
      */
     public void setExecutable(String executable, boolean translateFileSeparator) {
-        if (executable == null || executable.length() == 0) {
+        if (executable == null || executable.isEmpty()) {
             return;
         }
         this.executable = translateFileSeparator
@@ -468,7 +467,7 @@ public class Commandline implements Cloneable {
      * An empty or null toProcess parameter results in a zero sized array.
      */
     public static String[] translateCommandline(String toProcess) {
-        if (toProcess == null || toProcess.length() == 0) {
+        if (toProcess == null || toProcess.isEmpty()) {
             //no command? no string
             return new String[0];
         }

src/main/org/apache/tools/ant/types/CommandlineJava.java

@@ -756,8 +756,8 @@ public class CommandlineJava implements Cloneable {
      * @since Ant 1.6
      */
     public boolean haveClasspath() {
-        Path fullClasspath = classpath != null ? classpath.concatSystemClasspath("ignore") : null;
-        return fullClasspath != null && fullClasspath.toString().trim().length() > 0;
+        Path fullClasspath = classpath == null ? null : classpath.concatSystemClasspath("ignore");
+        return fullClasspath != null && !fullClasspath.toString().trim().isEmpty();
     }
 
     /**

src/main/org/apache/tools/ant/types/FilterSet.java

@@ -283,7 +283,7 @@ public class FilterSet extends DataType implements Cloneable {
         if (isReference()) {
             throw tooManyAttributes();
         }
-        if (startOfToken == null || "".equals(startOfToken)) {
+        if (startOfToken == null || startOfToken.isEmpty()) {
             throw new BuildException("beginToken must not be empty");
         }
         this.startOfToken = startOfToken;
@@ -310,7 +310,7 @@ public class FilterSet extends DataType implements Cloneable {
         if (isReference()) {
             throw tooManyAttributes();
         }
-        if (endOfToken == null || "".equals(endOfToken)) {
+        if (endOfToken == null || endOfToken.isEmpty()) {
             throw new BuildException("endToken must not be empty");
         }
         this.endOfToken = endOfToken;

src/main/org/apache/tools/ant/types/resources/MultiRootFileSet.java

@@ -79,9 +79,8 @@ public class MultiRootFileSet extends AbstractFileSet
         if (isReference()) {
             throw tooManyAttributes();
         }
-        if (dirs != null && dirs.length() > 0) {
-            final String[] ds = dirs.split(",");
-            for (final String d : ds) {
+        if (dirs != null && !dirs.isEmpty()) {
+            for (final String d : dirs.split(",")) {
                 baseDirs.add(getProject().resolveFile(d));
             }
         }

src/main/org/apache/tools/ant/types/selectors/ExtendSelector.java

@@ -56,7 +56,7 @@ public class ExtendSelector extends BaseSelector {
      * Instantiates the identified custom selector class.
      */
     public void selectorCreate() {
-        if (classname != null && classname.length() > 0) {
+        if (classname != null && !classname.isEmpty()) {
             try {
                 Class<?> c;
                 if (classpath == null) {

src/main/org/apache/tools/ant/types/selectors/TokenizedPath.java

@@ -64,9 +64,8 @@ public class TokenizedPath {
      * @param child the child, must not contain the file separator
      */
     public TokenizedPath(TokenizedPath parent, String child) {
-        if (parent.path.length() > 0
-            && parent.path.charAt(parent.path.length() - 1)
-               != File.separatorChar) {
+        if (!parent.path.isEmpty()
+            && parent.path.charAt(parent.path.length() - 1) != File.separatorChar) {
             path = parent.path + File.separatorChar + child;
         } else {
             path = parent.path + child;

src/main/org/apache/tools/ant/types/spi/Service.java

@@ -96,7 +96,7 @@ public class Service extends ProjectComponent {
                 "type attribute must be set for service element",
                 getLocation());
         }
-        if (type.length() == 0) {
+        if (type.isEmpty()) {
             throw new BuildException(
                 "Invalid empty type classname", getLocation());
         }

src/main/org/apache/tools/ant/util/DOMElementWriter.java

@@ -248,7 +248,7 @@ public class DOMElementWriter {
                     out.write("<?");
                     out.write(child.getNodeName());
                     String data = child.getNodeValue();
-                    if (data != null && data.length() > 0) {
+                    if (data != null && !data.isEmpty()) {
                         out.write(' ');
                         out.write(data);
                     }
@@ -398,7 +398,7 @@ public class DOMElementWriter {
         if (namespacePolicy.qualifyElements) {
             String uri = getNamespaceURI(element);
             String prefix = nsPrefixMap.get(uri);
-            if (prefix != null && !"".equals(prefix)) {
+            if (prefix != null && !prefix.isEmpty()) {
                 out.write(prefix);
                 out.write(":");
             }

src/main/org/apache/tools/ant/util/DeweyDecimal.java

@@ -60,7 +60,7 @@ public class DeweyDecimal implements Comparable<DeweyDecimal> {
 
         for (int i = 0; i < components.length; i++) {
             final String component = tokenizer.nextToken();
-            if (component.length() == 0) {
+            if (component.isEmpty()) {
                 throw new NumberFormatException("Empty component in string");
             }
 

src/main/org/apache/tools/ant/util/FileUtils.java

@@ -634,7 +634,7 @@ public class FileUtils {
      * @since Ant 1.7
      */
     public static boolean isContextRelativePath(String filename) {
-        if (!(ON_DOS || ON_NETWARE) || filename.length() == 0) {
+        if (!(ON_DOS || ON_NETWARE) || filename.isEmpty()) {
             return false;
         }
         char sep = File.separatorChar;
@@ -658,10 +658,10 @@ public class FileUtils {
      * @since Ant 1.6.3
      */
     public static boolean isAbsolutePath(String filename) {
-        int len = filename.length();
-        if (len == 0) {
+        if (filename.isEmpty()) {
             return false;
         }
+        int len = filename.length();
         char sep = File.separatorChar;
         filename = filename.replace('/', sep).replace('\\', sep);
         char c = filename.charAt(0);

src/main/org/apache/tools/ant/util/LayoutPreservingProperties.java

@@ -353,7 +353,7 @@ public class LayoutPreservingProperties extends Properties {
                 LogicalLine line;
                 if (comment) {
                     line = new Comment(logicalLineBuffer.toString());
-                } else if (logicalLineBuffer.toString().trim().length() == 0) {
+                } else if (logicalLineBuffer.toString().trim().isEmpty()) {
                     line = new Blank();
                 } else {
                     line = new Pair(logicalLineBuffer.toString());

src/main/org/apache/tools/ant/util/ResourceUtils.java

@@ -657,7 +657,7 @@ public class ResourceUtils {
             lineTokenizer.setIncludeDelims(true);
             String line = lineTokenizer.getToken(in);
             while (line != null) {
-                if (line.length() == 0) {
+                if (line.isEmpty()) {
                     // this should not happen, because the lines are
                     // returned with the end of line delimiter
                     out.newLine();

src/main/org/apache/tools/tar/TarEntry.java

@@ -995,7 +995,7 @@ public class TarEntry implements TarConstants {
                 if (isDirectory() && !name.endsWith("/")) {
                     name += "/";
                 }
-                if (prefix.length() > 0) {
+                if (!prefix.isEmpty()) {
                     name = prefix + "/" + name;
                 }
             }

src/main/org/apache/tools/tar/TarOutputStream.java

@@ -288,7 +288,7 @@ public class TarOutputStream extends FilterOutputStream {
                                                        TarConstants.LF_GNUTYPE_LONGNAME, "file name");
 
         final String linkName = entry.getLinkName();
-        boolean paxHeaderContainsLinkPath = linkName != null && linkName.length() > 0
+        boolean paxHeaderContainsLinkPath = linkName != null && !linkName.isEmpty()
             && handleLongName(entry, linkName, paxHeaders, "linkpath",
                               TarConstants.LF_GNUTYPE_LONGLINK, "link name");
 

src/main/org/apache/tools/zip/AsiExtraField.java

@@ -241,7 +241,7 @@ public class AsiExtraField implements ZipExtraField, UnixStat, Cloneable {
      * @since 1.1
      */
     public boolean isLink() {
-        return getLinkedFile().length() != 0;
+        return !getLinkedFile().isEmpty();
     }
 
     /**

src/tests/junit/org/apache/tools/ant/filters/TokenFilterTest.java

@@ -265,7 +265,7 @@ public class TokenFilterTest {
 
     public static class Capitalize implements TokenFilter.Filter {
         public String filter(String token) {
-            if (token.length() == 0) {
+            if (token.isEmpty()) {
                 return token;
             }
             return token.substring(0, 1).toUpperCase() + token.substring(1);

src/tests/junit/org/apache/tools/ant/launch/LocatorTest.java

@@ -65,7 +65,7 @@ public class LocatorTest {
      * @param enabled is the test enabled?
      */
     private void assertResolved(String uri, String expectedResult, String result, boolean enabled) {
-        if (enabled && expectedResult != null && expectedResult.length() > 0) {
+        if (enabled && expectedResult != null && !expectedResult.isEmpty()) {
             assertEquals("Expected " + uri + " to resolve to \n" + expectedResult + "\n but got\n"
                     + result + "\n", expectedResult, result);
         }

src/tests/junit/org/apache/tools/ant/taskdefs/CopyTest.java

@@ -302,7 +302,7 @@ public class CopyTest {
         try (BufferedReader reader = new BufferedReader(new FileReader(srcFile))) {
             originalContent = FileUtils.readFully(reader);
         }
-        assertTrue("Content missing in file " + srcFile, originalContent != null && originalContent.length() > 0);
+        assertTrue("Content missing in file " + srcFile, originalContent != null && !originalContent.isEmpty());
 
         // run the copy tests
         buildRule.executeTarget("testSelfCopy");

src/tests/junit/org/apache/tools/ant/taskdefs/DemuxOutputTask.java

@@ -54,7 +54,7 @@ public class DemuxOutputTask extends Task {
 
     protected void handleOutput(String line) {
         line = line.trim();
-        if (line.length() != 0 && !line.equals(randomOutValue)) {
+        if (!line.isEmpty() && !line.equals(randomOutValue)) {
             String message = "Received = [" + line + "], expected = ["
                 + randomOutValue + "]";
             throw new BuildException(message);
@@ -64,7 +64,7 @@ public class DemuxOutputTask extends Task {
 
     protected void handleErrorOutput(String line) {
         line = line.trim();
-        if (line.length() != 0 && !line.equals(randomErrValue)) {
+        if (!line.isEmpty() && !line.equals(randomErrValue)) {
             String message = "Received = [" + line + "], expected = ["
                 + randomErrValue + "]";
             throw new BuildException(message);

src/tests/junit/org/apache/tools/ant/taskdefs/ExecuteWatchdogTest.java

@@ -87,7 +87,7 @@ public class ExecuteWatchdogTest {
         int retcode = p.waitFor();
         if (retcode != 0) {
             String err = getErrorOutput(p);
-            if (err.length() > 0) {
+            if (!err.isEmpty()) {
                 System.err.println("ERROR:");
                 System.err.println(err);
             }

src/tests/junit/org/apache/tools/ant/util/FileUtilsTest.java

@@ -608,7 +608,7 @@ public class FileUtilsTest {
      */
     private void assertEqualsIgnoreDriveCase(String s1, String s2) {
         if ((Os.isFamily("dos") || Os.isFamily("netware"))
-            && s1.length() > 0 && s2.length() > 0) {
+            && !s1.isEmpty() && !s2.isEmpty()) {
             StringBuilder sb1 = new StringBuilder(s1);
             StringBuilder sb2 = new StringBuilder(s2);
             sb1.setCharAt(0, Character.toUpperCase(s1.charAt(0)));