Cause: You have a target You want to skip if a property is set, so You have unless=”property” as an attribute of the target, but all the targets this target depends on are still executed.
Cause: Ant failed to build Your program via javac even when You put the needed jars in an external build.properties file and reference them by pathelement or classpath refid.
Cause: You have installed Ant 1.6.x and now get Exception in thread “main” java.lang.NoClassDefFoundError. The cause of this is that there is an old version of ant somewhere in the class path or configuration.
Cause: You have installed Ant 1.6.x and now get java.lang.InstantiationException: org.apache.tools.ant.Main. The cause of this is that there is an old version of ant somewhere in the class path or configuration.
Cause: You have used the Ant jar or manifest related tasks, long lines in Your manifest were wrapped at 70 characters and the resulting jar did not work in Your application server
Description: Ant 1.7.0 doesn’t build from sources without JUnit
Cause: When building Ant 1.7.0 from the source release without junit.jar the build fails with the message “We cannot build the test jar unless JUnit is present”.
With Ant 1.7.0 ant-testutil.jar is added as part of the distribution and this causes a hard dependency on JUnit – at least in version 1.7.0.