Revert a regression, improve tests

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

@@ -56,9 +56,6 @@ public class Java extends Task {
     private static final String WRONG_ATTRIBUTES_MESSAGE =
             "Cannot use combination of 'classname', 'jar', 'module', 'sourcefile' attributes in same command";
 
-    private static final String WRONG_CLASSNAME_ATTRIBUTES_MESSAGE =
-            "Cannot use combination of 'classname', 'jar', 'sourcefile' attributes in same command";
-
     private CommandlineJava cmdl = new CommandlineJava();
     private Environment env = new Environment();
     private boolean fork = false;
@@ -385,7 +382,8 @@ public class Java extends Task {
      */
     public void setClassname(String s) throws BuildException {
         if (getCommandLine().getJar() != null || getCommandLine().getSourceFile() != null) {
-            throw new BuildException(WRONG_CLASSNAME_ATTRIBUTES_MESSAGE);
+            throw new BuildException(
+                    "Cannot use combination of 'classname', 'jar', 'sourcefile' attributes in same command");
         }
         getCommandLine().setClassname(s);
     }
@@ -400,7 +398,8 @@ public class Java extends Task {
      */
     public void setModule(String module) throws BuildException {
         if (getCommandLine().getJar() != null || getCommandLine().getSourceFile() != null) {
-            throw new BuildException(WRONG_CLASSNAME_ATTRIBUTES_MESSAGE);
+            throw new BuildException(
+                    "Cannot use combination of 'jar', 'module', 'sourcefile' attributes in same command");
         }
         getCommandLine().setModule(module);
     }

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

@@ -108,28 +108,28 @@ public class JavaTest {
     @Test
     public void testJarAndClassName() {
         thrown.expect(BuildException.class);
-        thrown.expectMessage("Cannot use combination of ");
+        thrown.expectMessage("Cannot use combination of 'classname', 'jar', 'sourcefile'");
         buildRule.executeTarget("testJarAndClassName");
     }
 
     @Test
     public void testClassnameAndJar() {
         thrown.expect(BuildException.class);
-        thrown.expectMessage("Cannot use combination of ");
+        thrown.expectMessage("Cannot use combination of 'classname', 'jar', 'module'");
         buildRule.executeTarget("testClassnameAndJar");
     }
 
     @Test
     public void testJarAndModule() {
         thrown.expect(BuildException.class);
-        thrown.expectMessage("Cannot use combination of ");
+        thrown.expectMessage("Cannot use combination of 'jar', 'module', 'sourcefile'");
         buildRule.executeTarget("testJarAndModule");
     }
 
     @Test
     public void testModuleAndJar() {
         thrown.expect(BuildException.class);
-        thrown.expectMessage("Cannot use combination of ");
+        thrown.expectMessage("Cannot use combination of 'classname', 'jar', 'module'");
         buildRule.executeTarget("testModuleAndJar");
     }