#178 NPE in PrettyPrinter when given invalid class decl

[Michael Bond]

A null pointer exception occurs if you try to process a Java file that uses an invalid class name:

public class Bug.java {

(It should be Bug instead of Bug.java)

It turns out this NPE occurs because ExceptionPrinter.getInstance() returns ExceptionPrinter.singleton without checking if it's null. Since other static methods in ExceptionPrinter first check if singleton is null (and initialize it if so), I think a good fix is to have ExceptionPrinter.getInstance() do the same.

Command line:

java PrettyPrinter Bug.java

Exception stack trace:

NullPointerException:
at net.sourceforge.jrefactory.factory.ParserFactory.getAbstractSyntaxTree(ParserFactory.java:46)
at org.acm.seguin.pretty.PrettyPrintFile.apply(PrettyPrintFile.java:102)
at org.acm.seguin.tools.builder.PrettyPrinter.visit(PrettyPrinter.java:77)
at org.acm.seguin.io.DirectoryTreeTraversal.traverse(DirectoryTreeTraversal.java:91)
at org.acm.seguin.io.DirectoryTreeTraversal.run(DirectoryTreeTraversal.java:43)
at org.acm.seguin.tools.builder.PrettyPrinter.prettyPrinter(PrettyPrinter.java:163)
at org.acm.seguin.tools.builder.PrettyPrinter.main(PrettyPrinter.java:143)
at PrettyPrinter.main(PrettyPrinter.java:54)

Hope this helps. Please let me know if you'd like more info.