Converter tests:

Change test data files extension to "java"

j2k/tests/testData/ast/issues/comments.java

@@ -0,0 +1,66 @@
+//file
+// This is an end-of-line comment
+
+/*
+This is a block comment
+*/
+
+
+/*doc comment of class*/
+//one line comment of class
+//another one
+/*another doc*/
+class C {
+    // This is a class comment
+
+    /**
+    * This is a field doc comment.
+    */
+    private int i;
+
+    /**
+    * This is a function doc comment.
+    */
+    public void foo() {
+    /* This is a function comment */
+    }
+
+    //simple one line comment for function
+    void f1() {
+    }
+
+    //simple one line comment for field
+    int j;
+
+    //double c style
+    //comment before function
+    void f2() {
+    }
+
+    //double c style
+    //comment before field
+    int k;
+
+    //combination
+    /** of
+    */
+    //
+    /**
+    * different
+    */
+    //comments
+    void f3() {}
+
+    //combination
+    /** of
+    */
+    //
+    /**
+    * different
+    */
+    //comments
+    int l;
+
+    /*two*/ /*comments*//*line*/
+    int z;
+}