Problem: WHile compiling an applet, javac got a null pointer exception.

The trace is as follows ......

javac memObjTest1_mt.java
java.lang.NullPointerException
        at sun.tools.tree.MethodExpression.inline(MethodExpression.java:248)
        at sun.tools.tree.ExpressionStatement.inline(ExpressionStatement.java:51)
        at sun.tools.tree.IfStatement.inline(IfStatement.java:77)
        at sun.tools.tree.CompoundStatement.inline(CompoundStatement.java:65)
        at sun.tools.tree.ForStatement.inline(ForStatement.java:90)
        at sun.tools.tree.CompoundStatement.inline(CompoundStatement.java:65)
        at sun.tools.tree.ForStatement.inline(ForStatement.java:84)
        at sun.tools.tree.CompoundStatement.inline(CompoundStatement.java:65)
        at sun.tools.tree.ForStatement.inline(ForStatement.java:90)
        at sun.tools.tree.CompoundStatement.inline(CompoundStatement.java:65)
        at sun.tools.tree.ForStatement.inline(ForStatement.java:84)
        at sun.tools.tree.CompoundStatement.inline(CompoundStatement.java:65)
        at sun.tools.javac.SourceField.inline(SourceField.java:293)
        at sun.tools.javac.SourceField.code(SourceField.java:367)
        at sun.tools.javac.SourceClass.compileClass(SourceClass.java:564)
        at sun.tools.javac.SourceClass.compile(SourceClass.java:527)
        at sun.tools.javac.Main.compile(Main.java:193)
        at sun.tools.javac.Main.main(Main.java:289)
.//memObjTest1_mt.java:19: Class myThread already defined in memObjTest1_mt.java.
class myThread implements Runnable {
      ^
.//memObjTest1_mt.java:31: Class memObjTest1_mt not found in type declaration.
        static memObjTest1_mt myapplet; // Remember applet for graphics
                                      ^
.//memObjTest1_mt.java:53: Class memObjTest1_mt not found in void run().
                                myapplet.paint(myapplet.getGraphics());
                                                                   ^
.//memObjTest1_mt.java:56: Class memObjTest1_mt not found in void run().
                        myapplet.allClear();
                                         ^
.//memObjTest1_mt.java:70: Undefined variable: this
                        if((this.thrNo == 0) && (done % xfactor) == 0){
                            ^
.//memObjTest1_mt.java:89: Class memObjTest1_mt not found in type declaration.
        public void setApplet(memObjTest1_mt ma){
                    ^
.//memObjTest1_mt.java:97: Class memObj already defined in memObjTest1_mt.java.
class memObj {
      ^
.//memObjTest1_mt.java:114: Class memObjTest1 already defined in memObjTest1_mt.
public class memObjTest1 extends java.applet.Applet {
             ^
             ^
error: An exception has occurred in the compiler; please file a bug report (###@###.###).
9 errors
 
------------------------- End of trace ----------------------------

I made some changes to the applet and javac had no problems afterwords.