FULL PRODUCT VERSION :
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux 3.13.0-34-generic #60-Ubuntu SMP Wed Aug 13 15:45:27 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

A DESCRIPTION OF THE PROBLEM :
I upgraded from 1.8.0_11 to 1.8.0_20 and suddenly I cannot compile my project anymore.
javac crashes with a NullPointerException.


REGRESSION. Last worked in version 8u11

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_11"
Java(TM) SE Runtime Environment (build 1.8.0_11-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.11-b03, mixed mode)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
git clone https://github.com/xylo/LazySeq.git
cd LazySeq
mvn package

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The expected result is that javac does not crash.
ACTUAL -
javac crashes with a NullPointerException

ERROR MESSAGES/STACK TRACES THAT OCCUR :
% mvn package
[INFO] Scanning for projects...
[WARNING]
[WARNING] Some problems were encountered while building the effective model for com.blogspot.nurkiewicz.lazyseq:lazyseq:jar:0.0.1-SNAPSHOT
[WARNING] 'build.plugins.plugin.version' for org.apache.maven.plugins:maven-source-plugin is missing. @ line 79, column 12
[WARNING]
[WARNING] It is highly recommended to fix these problems because they threaten the stability of your build.
[WARNING]
[WARNING] For this reason, future Maven versions might no longer support building such malformed projects.
[WARNING]
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building LazySeq 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-resources-plugin:2.3:resources (default-resources) @ lazyseq ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/stefan/tmp/LazySeqTest/LazySeq/src/main/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ lazyseq ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:2.3:testResources (default-testResources) @ lazyseq ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] skip non existing resourceDirectory /home/stefan/tmp/LazySeqTest/LazySeq/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.1:testCompile (default-testCompile) @ lazyseq ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 8 source files to /home/stefan/tmp/LazySeqTest/LazySeq/target/test-classes
An exception has occurred in the compiler (1.8.0_20). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
        at com.sun.tools.javac.code.Types.isConvertible(Types.java:290)
        at com.sun.tools.javac.comp.Check.assertConvertible(Check.java:922)
        at com.sun.tools.javac.comp.Check.checkMethod(Check.java:876)
        at com.sun.tools.javac.comp.Attr.checkMethod(Attr.java:3838)
        at com.sun.tools.javac.comp.Attr.checkIdInternal(Attr.java:3615)
        at com.sun.tools.javac.comp.Attr.checkMethodIdInternal(Attr.java:3522)
        at com.sun.tools.javac.comp.Attr.checkMethodId(Attr.java:3501)
        at com.sun.tools.javac.comp.Attr.checkId(Attr.java:3488)
        at com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3370)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1897)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1843)
        at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1465)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:649)
        at com.sun.tools.javac.comp.Attr.visitVarDef(Attr.java:1093)
        at com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:852)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
        at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:692)
        at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1142)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:909)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
        at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1035)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:778)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
        at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4342)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4252)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4181)
        at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4156)
        at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1248)
        at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:901)
        at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:860)
        at com.sun.tools.javac.main.Main.compile(Main.java:523)
        at com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:129)
        at com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:138)
        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.TestCompilerMojo.execute(TestCompilerMojo.java:152)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
        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:84)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:483)
        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
[INFO] 1 error
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.235s
[INFO] Finished at: Mon Aug 25 11:45:29 CEST 2014
[INFO] Final Memory: 14M/169M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.1:testCompile (default-testCompile) on project lazyseq: Compilation failure
[ERROR] An unknown compilation problem occurred
[ERROR] -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
I found out that the compiler crashes only in the test classes, especially in the LazySeqReduceTest and this test can be cut down to the following class:

public class LazySeqReduceTest extends AbstractBaseTestCase {

@Test
public void test() throws Exception {
final LazySeq<String> empty = LazySeq.empty();
final int totalSum = empty.reduce(0, (acc, i) -> acc + i.length());
}

}


Thus, seemingly the new javac does not like the reduce method of LazySeq, but I have no idea why.
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Go back to JDK 1.8.0_11.