hFULL PRODUCT VERSION :
java version "1.8.0_20-ea"
Java(TM) SE Runtime Environment (build 1.8.0_20-ea-b05)
Java HotSpot(TM) Client VM (build 25.20-b05, mixed mode, sharing)

EXTRA RELEVANT SYSTEM CONFIGURATION :
Compiling with IntelliJIdea 12.1.6

A DESCRIPTION OF THE PROBLEM :
When using JDK 1.8.0_20 to compile JSPs that reference classes compiled with IntelliJIdea 12.1.6 with @NotNull assertions added I get a compiler crash.  I provide a reduced test case, 

REGRESSION.  Last worked in version 8

ADDITIONAL REGRESSION INFORMATION: 
java version "1.8.0_20-ea"
Java(TM) SE Runtime Environment (build 1.8.0_20-ea-b05)
Java HotSpot(TM) Client VM (build 25.20-b05, mixed mode, sharing)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Compile BugImported.java with IntelliJIdea 12.1.6 using 1.8.0_20 as the project JDK, or use the attached BugImported.class
2. From the command line, compile Bug.java with the class file from step 1 in the classpath


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Bug.java should compile correctly
ACTUAL -
The compiler crashes

ERROR MESSAGES/STACK TRACES THAT OCCUR :
An exception has occurred in the compiler (1.8.0_20-ea). Please file a bug at the Java Developer Connection (http://java
or duplicates. Include your program and the following diagnostic in your report.  Thank you.
java.lang.ClassCastException: com.sun.tools.javac.code.Symbol$ClassSymbol cannot be cast to com.sun.tools.javac.util.Name
        at com.sun.tools.javac.jvm.ClassReader.readName(ClassReader.java:597)
        at com.sun.tools.javac.jvm.ClassReader.setParameterNames(ClassReader.java:2125)
        at com.sun.tools.javac.jvm.ClassReader.readMethod(ClassReader.java:2026)
        at com.sun.tools.javac.jvm.ClassReader.readClass(ClassReader.java:2229)
        at com.sun.tools.javac.jvm.ClassReader.readClassFile(ClassReader.java:2301)
        at com.sun.tools.javac.jvm.ClassReader.fillIn(ClassReader.java:2488)
        at com.sun.tools.javac.jvm.ClassReader.complete(ClassReader.java:2419)
        at com.sun.tools.javac.jvm.ClassReader.access$000(ClassReader.java:76)
        at com.sun.tools.javac.jvm.ClassReader$1.complete(ClassReader.java:240)
        at com.sun.tools.javac.code.Symbol.complete(Symbol.java:560)
        at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1024)
        at com.sun.tools.javac.jvm.ClassReader.loadClass(ClassReader.java:2600)
        at com.sun.tools.javac.comp.Resolve.loadClass(Resolve.java:1863)
        at com.sun.tools.javac.comp.Resolve.findIdentInPackage(Resolve.java:2102)
        at com.sun.tools.javac.comp.Attr.selectSym(Attr.java:3358)
        at com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3257)
        at com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:1891)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:596)
        at com.sun.tools.javac.comp.Attr.attribType(Attr.java:658)
        at com.sun.tools.javac.comp.Attr.attribType(Attr.java:651)
        at com.sun.tools.javac.comp.MemberEnter.attribImportType(MemberEnter.java:836)
        at com.sun.tools.javac.comp.MemberEnter.visitImport(MemberEnter.java:556)
        at com.sun.tools.javac.tree.JCTree$JCImport.accept(JCTree.java:571)
        at com.sun.tools.javac.comp.MemberEnter.memberEnter(MemberEnter.java:435)
        at com.sun.tools.javac.comp.MemberEnter.memberEnter(MemberEnter.java:447)
        at com.sun.tools.javac.comp.MemberEnter.visitTopLevel(MemberEnter.java:526)
        at com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:518)
        at com.sun.tools.javac.comp.MemberEnter.memberEnter(MemberEnter.java:435)
        at com.sun.tools.javac.comp.MemberEnter.complete(MemberEnter.java:1038)
        at com.sun.tools.javac.code.Symbol.complete(Symbol.java:560)
        at com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1024)
        at com.sun.tools.javac.comp.Enter.complete(Enter.java:497)
        at com.sun.tools.javac.comp.Enter.main(Enter.java:475)
        at com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:985)
        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.main.Main.compile(Main.java:381)
        at com.sun.tools.javac.main.Main.compile(Main.java:370)
        at com.sun.tools.javac.main.Main.compile(Main.java:361)
        at com.sun.tools.javac.Main.compile(Main.java:56)
        at com.sun.tools.javac.Main.main(Main.java:42)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
---- File BugImported.class (base64 encoded)

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dHJpbmc7AQAjTG9yZy9qZXRicmFpbnMvYW5ub3RhdGlvbnMvTm90TnVsbDsBACJqYXZhL2xhbmcv
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ZXRob2RQYXJhbWV0ZXJzAQAKU291cmNlRmlsZQAhAAIABAAAAAAAAwABAAYABwABADIAAAAvAAEA
AQAAAAUqtwAJsQAAAAIAMwAAAAwAAQAAAAUACgALAAAANAAAAAYAAQAAAAUACgAMAA0ABAAyAAAA
VgAEAAEAAAAfKscADbsAEFkSErcAFb8SF1nHAA27ABlZEhu3ABy/sAAAAAMAMwAAAAwAAQAAAB8A
HQAeAAAANAAAAAYAAQAOAAoANQAAAAcAAg5PBwAgADYAAAAGAAEADgAAADcAAAAHAQABAA4AAAA4
AAAABQEAEQAQAAkAIQAiAAIAMgAAADoAAgABAAAADLIAKBIXuAAqtgAvsQAAAAIAMwAAAAwAAQAA
AAwAMAAxAAAANAAAAAoAAgAAABAACwARADgAAAAFAQAZAAAAAQA5AAAAAgAF


---- File Bug.java

package bug;

import bug.BugImported;

public class Bug
{
}


--- For reference, file BugImported.java

package bug;

import org.jetbrains.annotations.NotNull;

public class BugImported
{
	@NotNull
	private static String getString (@NotNull final String string)
	{
		return "";
	}


	public static void main (String[] args)
	{
		System.out.println (getString (""));
	}

}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Disable "Add @NotNull assertions" in compile options for IntelliJIdea