Troubleshooting

• Compilation
• Execution
• Deployment

Compilation

• When compiling my project, the JET Optimizer crashes
• When compiling my project, the JET Optimizer issues an "out of memory" message and then terminates
• When compiling my project, intensive memory paging occurs

When compiling my project, the JET Optimizer crashes

Though we put a lot of efforts in testing, the last bug in Excelsior JET is yet to be found. If you encountered a bug in the JET Optimizer, or if it crashed while compiling your application, please do the following:

• Upgrade to the latest version of Excelsior JET. There is a chance that the problem was fixed after your current version was released.
• Install the latest maintenance pack. We routinely issue MPs to all Excelsior JET versions currently supported, fixing major issues experienced by our customers.
• Contact Excelsior support. If possible, send us a stripped down version of your application, so we can reproduce the problem on our end. Information about your hardware and software environment, as well as the version and edition of Excelsior JET in use will also help.

When compiling my project, the JET Optimizer issues an "out of memory" message and then terminates

Reason: The current setting of memory usage limit in the JET’s compiler is too small for compilation of your program.

Resolution: Increase the value of COMPILERHEAP in in your project file, for instance:

    -compilerheap=90000000

When compiling my project, intensive memory paging occurs

Reason: The current setting of compiler memory usage limit is too large for your system.

Resolution: Close all applications that you do not need at the moment. If it does not help, reduce the size of compiler heap through decreasing the value of COMPILERHEAP in your project file or on the command line, for instance:

    jc MyApp.jar -compilerheap=80000000

The default value of COMPILERHEAP may be inspected by running jc in the EQUATIONS submode:

    jc =e

Execution

• Diagnostics of unrecoverable errors: TRAP#N
• HOWTO
• How do I set Java properties at the very startup of my application?
• The compiled application cannot find resources (images, etc.)
• OutOfMemoryError is thrown during execution

Diagnostics of unrecoverable errors: TRAP#N

Unrecoverable errors are those preventing the program from further execution, that is, the errors (crashes) which cannot be handled.

A known example is access violation that occurs when reading/writing memory at an address to which no memory page was mapped or transferring control to such a region. If a JET-compiled application runs into the problem, the Runtime prints TRAP#3 message and execution abnormally terminates.

Of course, it should never happen in a pure Java application but, unfortunately, it may happen due to:

• bugs in the native method libraries used by the application
• JNI misuses (correct usage of JNI is tricky for inexperienced programmers)
• operating system malfunction (yes, we found a few examples when debugging customers’ applications)
• bugs in the JET Optimizer or Runtime escaped Excelsior QA (despite it’s a rare case for the matured versions released last years, it may happen.)

Often, the errors are volatile, that is, hardly reproducible. To address the problem, the JET Runtime includes a special diagnostic facility. If an unrecoverable error occurs, the Runtime collects various information about the application state, logs it into a file, and prints the error message referencing that file.

HOWTO

How do I set Java properties at the very startup of my application?

Properties may be set at compile time using the JETVMPROP equation or at launch time using the JETVMPROP environment variable. See Java system properties for details.

The compiled application cannot find resources (images, etc.)

Resolution: Use resource packing.

OutOfMemoryError is thrown during execution

Reason: Application’s heap size is set to adaptive, and there is not enough available physical memory on the system, or the explicit setting is too low.

Resolution: Adjust the application’s heap size setting:

• Using the Control Panel: go to the Options page and set the Heap Size field to the desired value (see Memory Management.)
• At launch time: set the jet.gc.heaplimit property through the environment variable JETVMPROP in a batch file, e.g.:

      SET JETVMPROP=-Djet.gc.heaplimit:90m
      MyApp 
  

More information on memory management settings of the JET Runtime may be found in Memory management.

Reason: Your application runs too many threads.

Resolution: Reduce thread stack size:

• Using the Control Panel: go to the Options page and decrease the value of Stack size (see Stack size.)
• Using the command line compiler: decrease the value of STACKLIMIT in jc.cfg, in your project file, or on the command line, for instance:

      jc MyApp.jar -stacklimit=100000

  The default value of STACKLIMIT may be inspected by running jc in the EQUATIONS submode:

      jc =e

Deployment

• My application does not work on another system
• How do I build my application as a single executable file?

My application does not work on another system

See Chapter Deployment automation for information on deployment of the compiled applications.

How do I build my application as a single executable file?

Excelsior JET is not able to create a single all-inclusive executable that can be deployed to target machines by simply copying. Instead, JET offers the following deployment options:

• Preparing a self-contained directory that includes the executable(s) and all necessary supplemental files. Such a directory can be deployed to other computers by simply copying. No extra settings are required to run the included executables.
• Creating a self-extracting setup with command-line or GUI interface.

See Chapter Deployment automation for information on JET deployment automation facilities.

If you are interested in creating single executables for reasons other than deployment, please fill out the form at

    http://www.excelsior-usa.com/jetfr.html

and describe your requirements for that feature.