A list of changes made between versions 3.5 and 4 are listed here .

Known bugs etc

While there are no known bugs in JHawk per se there are a couple of issues that may arise.

1. The introduction of the 'assert' keyword in Java 1.4

This version of JHawk will parse Java code written for versions of the Java compiler up to and including Java 1.4. Prior to Java 1.4 it was possible to use the word 'assert' in your code without any problem. As 'assert' is now a keyword code containing 'assert' in a position where it is deemed as being possibly a keyword e.g. package, class or method names will not compile. JHawk will also detect this as a lexical error. It will continue processing other files but a message to the effect that 'assert' was detected in the code will appear in the system log.

2. Running on Linux
You may see the following message (or something like it) when trying to run JHawk on Linux -

     Warning: Cannot convert string "Escape,_Key_Cancel" to type VirtualBinding
     Warning: Cannot convert string "Home,_Key_Begin" to type VirtualBinding
     Warning: Cannot convert string "F1,_Key_Help" to type VirtualBinding 
     Warning: Cannot convert string "ShiftF10,_Key_Menu" to type VirtualBinding
     Warning: Cannot convert string "F10,Shift_Key_Menu" to type VirtualBinding
     Warning: Cannot convert string "KP_Enter,Key_Execute" to type VirtualBinding
     Warning: Cannot convert string "AltReturn,Alt_Key_KP_Enter" to type VirtualBinding

This message is harmless but you can remove it by running the following -

xprop -root -remove _MOTIF_DEFAULT_BINDINGS

You can find a full reference to this problem at http://www.mail-archive.com/java-linux@java.blackdown.org/msg15007.html

3. Drive A: Not Ready Error on Windows

This is due to a bug in JRE 1.3 where instantiating a JFileChooser with the default FileSystemView (which JHawk does when it starts up) will cause a "drive A: not ready" error every time. This is because java.io.File.listRoots() does a SecurityManager.checkRead() which causes the OS to try to access drive A: even when there is no disk, causing an annoying "abort, retry, ignore" popup message.

This is fixed by upgrading to version 1.4. of the JRE.