Error when compiling from the source

I use the "git clone https://github.com/stratosphere/stratosphere.git" command, and then I use "mvn clean package -DskipTests" to compile but it goes wrong. My java compiler version is javac 1.7.0_55. The error message is follow:

[INFO] — maven-compiler-plugin:3.1:compile (default-compile) @ stratosphere-java —
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 209 source files to /Users/wilsoncao/Documents/stratosphere/stratosphere-java/target/classes
?????? (1.6.0_65) ?г??쳣 ????? Bug Parade û?ҵ??ô??????? Java Developer Connection (http://java.sun.com/webapps/bugreport) ?Ըô???й鵵 ?ڱи??ij???????????Ϣ??лл?ĺ???
java.lang.NullPointerException
at com.sun.tools.javac.comp.Check.checkCompatibleConcretes(Check.java:1213)
at com.sun.tools.javac.comp.Check.checkCompatibleSupertypes(Check.java:1567)
at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:2674)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2628)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2584)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2584)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2584)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:2564)
at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1045)
at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:768)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:730)
at com.sun.tools.javac.main.Main.compile(Main.java:353)
at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:115)
at org.codehaus.plexus.compiler.javac.JavaxToolsCompiler.compileInProcess(JavaxToolsCompiler.java:126)
at org.codehaus.plexus.compiler.javac.JavacCompiler.performCompile(JavacCompiler.java:169)
at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:785)
at org.apache.maven.plugin.compiler.CompilerMojo.execute(CompilerMojo.java:129)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:133)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:108)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:76)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:116)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:361)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:155)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:584)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:213)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:157)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR :
[INFO] -------------------------------------------------------------
[ERROR] An unknown compilation problem occurred

---------------- Imported from GitHub ----------------
Url: https://github.com/stratosphere/stratosphere/issues/906
Created by: wilsoncao
Labels:
Created at: Wed Jun 04 17:48:54 CEST 2014
State: closed