FULL PRODUCT VERSION :
java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b18)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
The java compiler generates a NPE when trying to compile the given source.
May be related to
http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8057800

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to compile given source code, like:
$"C:\Program Files\Java\jdk1.8.0_25\bin\javac" CompilerBug.java


ERROR MESSAGES/STACK TRACES THAT OCCUR :
$"C:\Program Files\Java\jdk1.8.0_25\bin\javac" CompilerBug.java
An exception has occurred in the compiler (1.8.0_25). Please file a bug at the Java Developer Connection (http://java.sun.com/webapps/bugreport) after checking the Bug Parade for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
        at com.sun.tools.javac.code.Types.intersect(Types.java:3381)
        at com.sun.tools.javac.code.Types.lub(Types.java:3600)
        at com.sun.tools.javac.comp.Infer$InferenceStep$2.solve(Infer.java:1358)
        at com.sun.tools.javac.comp.Infer$InferenceContext.solveBasic(Infer.java:2247)
        at com.sun.tools.javac.comp.Infer$InferenceContext.access$600(Infer.java:1912)
        at com.sun.tools.javac.comp.Infer$GraphSolver.solve(Infer.java:1587)
        at com.sun.tools.javac.comp.Infer$InferenceContext.solve(Infer.java:2198)
        at com.sun.tools.javac.comp.Infer$InferenceContext.solve(Infer.java:2190)
        at com.sun.tools.javac.comp.Infer$InferenceContext.solve(Infer.java:2205)
        at com.sun.tools.javac.comp.Infer.instantiateMethod(Infer.java:186)
        at com.sun.tools.javac.comp.Resolve.rawInstantiate(Resolve.java:564)
        at com.sun.tools.javac.comp.Resolve.selectBest(Resolve.java:1431)
        at com.sun.tools.javac.comp.Resolve.findMethodInScope(Resolve.java:1618)
        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1689)
        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1662)
        at com.sun.tools.javac.comp.Resolve.findFun(Resolve.java:1822)
        at com.sun.tools.javac.comp.Resolve$8.doLookup(Resolve.java:2383)
        at com.sun.tools.javac.comp.Resolve$BasicLookupHelper.lookup(Resolve.java:3074)
        at com.sun.tools.javac.comp.Resolve.lookupMethod(Resolve.java:3325)
        at com.sun.tools.javac.comp.Resolve.lookupMethod(Resolve.java:3310)
        at com.sun.tools.javac.comp.Resolve.resolveMethod(Resolve.java:2379)
        at com.sun.tools.javac.comp.Attr.visitIdent(Attr.java:3170)
        at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:2011)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1843)
        at com.sun.tools.javac.tree.JCTree$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:656)
        at com.sun.tools.javac.comp.Attr.visitExec(Attr.java:1611)
        at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1296)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:607)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:676)
        at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:692)
        at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1142)
        at com.sun.tools.javac.tree.JCTree$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.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 ----------
import java.util.concurrent.Callable;

public class CompilerBug {

    public static <T> T execSafe(Callable<T> task, T defaultReturnValue) {
        return execSafe(task, defaultReturnValue, "");
    }

    public static <T> T execSafe(Callable<T> task, T defaultReturnValue, String errorMsg) {
        try {
            return task.call();
        } catch (Exception e) {
            System.err.println(errorMsg);
            e.printStackTrace();
            return defaultReturnValue;
        }
    }

    public static void execSafe(Runnable task, String errorMsg) {
        try {
            task.run();
        } catch (Exception e) {
            System.err.println(errorMsg);
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        new CompilerBug().callRunnable();
        new CompilerBug().callCallable();
    }

    private void callRunnable() {
        execSafe(() -> System.out.println("Hi, bugs!"), "Error occurred");
    }

    private Boolean callCallable() {
        return execSafe(() -> {
            System.out.println("Hi, bugs!");
            return false;
        }, null, "Error occurred");
    }
}
---------- END SOURCE ----------