Frequently asked questions

• General questions
• The decompilation and disassembly processes
• Functions and features
• Registering an Evaluation Copy

• Help menu

• NMI's Java Code Viewer is unable to decompile or disassemble a specific Java class file. How is this possible?
  First of all, a file can be corrupt or may not be a Java class at all. Check the Log-file for error-messages; these error messages are explained in console help of these help topics. If you want to be sure, you may send an e-mail with a description of your findings to support@njcv.htmlplanet.com. Please attach the particular class file to your e-mail.

• After decompiling a Java class, I cannot compile the generated source-code file. The source-code shows peculiar characters. What is the problem?
  1. The first possibility is that the name of a Java class file is not exactly the same as the name of the actual Java class. Try renaming the generated source-code file to the actual class name.
  2. A second possibility is that you are trying to compile a generated inner-class source-code file or a source-code file making use of inner-classes. NMI's Java Code Viewer decompiles all Java class files separately, so you have to make sure you have decompiled all required Java class files. From all generated source-code files you need to compose one complete source-code file.
  3. Java is rapidly going forward and the Jad decompilation engine is updated frequently. Minor errors may occur during the decompilation process, resulting in source-code that is not 100% correct. Before compiling the generated source-code file, correct these errors manually. See the questions and answers below as well.

• Why does NMI's Java Code Viewer sometimes fail to generate throws clause in the method declarations like the one in: int divide(int a, int b) throws DivideByZero { ... }?
  Those throws clauses are represented in Java class files by Exceptions attributes. Because the Java Virtual Machine itself doesn't use these attributes (at least, in the common implementations) they can be stripped out of class files or not be generated by the compiler at all. NMI's Java Code Viewer has no way of restoring that information in full if it is missing from the class file.

• Why does NMI's Java Code Viewer sometimes generate weird-looking static fields like class$java$lang$Float and static methods class$(String)?
  These fields/methods are the internal representations of [[file.class]] expressions and are automatically generated by the compiler. NMI's Java Code Viewer doesn't convert all that back into the original expression, but apparently the JDK compiler is able to compile "the long format" successfully.

• NMI's Java Code Viewer fails to decompile my class file, it spits out a bunch of gotos and JVM instructions. Why is that?
  Either the class file has been obfuscated or it was produced by non-JDK Java compiler. NMI's Java Code Viewer works best on class files generated by Java compilers from Sun's JDK.

• In a generated file, in stead of the source file name I'm getting a message like this: 070DWARNING: Decompiling this code may violate your licensing agreement0A1A0C. What does this mean?
  By using NMI's Java Code Viewer you may accidently circumvent copy protection or you may decompile (portions of) copyright software programs. Without permission of the copyright holders, this may be illegal. When you are getting a message with such a warning, you are violating copyrights unless you have permission of the copyright holders. NMI's Java Code Viewer and its owner cannot, under any circumstances, be held liable for violation of copyrights caused by registered and unregistered users of NMI's Java Code Viewer. Also see the Limited warranty section of the License agreement.

• When processing a selection of valid Java class files, NMI's Java Code Viewer sometimes seems to get stuck on the first Java class file. What is wrong?
  This error may occasionally happen on Windows platforms using Japanese, Chinese or Korean character sets. If this appears to be the case, please contact us at support@njcv.htmlplanet.com and give us a full description of the occuring problem, your system and its operating system. Also attach some of the Java class files, causing the problem, to your e-mail.

• I want to register my copy NMI's Java Code Viewer. How can I get a license?
  You can order a license online on the following web page: http://njcv.htmlplanet.com/order.html. If you have any questions about ordering and pricing, please e-mail us at sales@njcv.htmlplanet.com.

• On starting NMI's Java Code Viewer, on opening a new directory or when I want to start processing Java class files, a message pops up rambling about an Evaluation Copy. What should I do?
  There are a few limitations using the Evaluation Copy. Only one directory can be opened per session, only one selection of Java class files can be decompiled or disassembled and all Java class files cannot automatically be selected. These limitations are lifted if you register your copy of NMI's Java Code Viewer.

• On entering the registration key, NMI's Java Code Viewer does not lift the limitations of the Evaluation Copy. What am I doing wrong?
  
  1. First of all, it's important that you enter your (company's) name correctly. This means that it should be spelled in exactly the same way as in the e-mail message containing your registration key. Note that NMI's Java Code Viewer is case-sensitive and that spaces and punctuation marks do matter.
  2. Secondly, on entering your registration key, NMI's Java Code Viewer checks if it is located in its original location on the machine where it was originally installed. This means that by copying or moving NMI's Java Code Viewer to another directory or another computer, registration will not be accepted. You must re-install NMI's Java Code Viewer.

• My registered copy of NMI's Java Code Viewer turned into an Evaluation Copy again. What happened?
  You've probably moved or copied NMI's Java Code Viewer to another directory or machine. Move the program back to its original location or re-install it in the new location.