Downloading scientific workflow kepler: Error ant in build .xml

Question

When I try to download my kepler engine using cmd, I face this problem for the ant in the build.xml. I install the java, ant, and svn versions, and I don't have any problems.

C:\Users\lenovo\kepler\build-area>ant change-to -Dsuite=kepler Buildfile: C:\Users\lenovo\kepler\build-area\build.xml

BUILD FAILED C:\Users\lenovo\kepler\build-area\build.xml:4: The following error occurred while executing this line: C:\Users\lenovo\kepler\build-area\settings\taskdefs.xml:5: java.lang.UnsupportedClassVersionError: org/kepler/build/Maven : Unsupported major.minor version 52.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:800) at org.apache.tools.ant.AntClassLoader.defineClassFromData(AntClassLoader.java:1150) at org.apache.tools.ant.AntClassLoader.getClassFromStream(AntClassLoader.java:1318) at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1374) at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1335) at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1090) at java.lang.ClassLoader.loadClass(ClassLoader.java:358) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:278) at org.apache.tools.ant.taskdefs.Definer.addDefinition(Definer.java:580) at org.apache.tools.ant.taskdefs.Definer.execute(Definer.java:238) at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293) at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106) at org.apache.tools.ant.Task.perform(Task.java:348) at org.apache.tools.ant.Target.execute(Target.java:437) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:169) at org.apache.tools.ant.taskdefs.ImportTask.importResource(ImportTask.java:225) at org.apache.tools.ant.taskdefs.ImportTask.execute(ImportTask.java:166) at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:293) at sun.reflect.GeneratedMethodAccessor4.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106) at org.apache.tools.ant.Task.perform(Task.java:348) at org.apache.tools.ant.Target.execute(Target.java:437) at org.apache.tools.ant.helper.ProjectHelper2.parse(ProjectHelper2.java:180) at org.apache.tools.ant.ProjectHelper.configureProject(ProjectHelper.java:93) at org.apache.tools.ant.Main.runBuild(Main.java:832) at org.apache.tools.ant.Main.startAnt(Main.java:236) at org.apache.tools.ant.launch.Launcher.run(Launcher.java:286) at org.apache.tools.ant.launch.Launcher.main(Launcher.java:112)

Total time: 0 seconds

Answer 1

The Kepler FAQ "system requirements" explicitly states:

Kepler is a large application that has substantial hardware requirements.
These include 512MB of RAM (1 GB or more recommended), at least 300 MB of disk space, and at least a 2GHz CPU. Kepler runs on modern Windows, Macintosh (OS X), and Linux systems using Java 1.8 or greater.

As explained here, you error message means you are not using the right JDK. (JDK8 or more)

Check out Instructions and Overview of the Kepler Build System. / Assumptions

1. You are running Java 1.8. To test this assumption type: "java -version"
2. You are using Ant 1.8.2. To test this assumption type: "ant -version"
3. You have installed Maven 3.0.3 or newer. To test this assumption: "mvn --version"
4. You have installed an SVN client, v1.6. To test this assumption type: "svn --version"
5. For development with Eclipse these have been tested with Eclipse Ganymede and SVN 1.5.5, with Subclipse 1.4.7.