This TechNote describes an issue with compiler performance issues caused by Sun's Java JRE/JDK 1.4.2_10 or earlier or 1.5.0_05 or earlier.


Flex Builder Eclipse plug-in installation

  • Ensure that you are running the supported version of Eclipse: 3.1.1
  • Install a 1.4.2 JRE/JDK with a minor version later than 10. For example, 1.4.2_11, or a 1.5 with a minor version later than 05, for example, 1.5.0_06.
  • If you have multiple versions of the JRE/JDK on your machine, make sure that you set the newly installed version as your default JRE/JDK by putting it at the beginning of your system PATH environment variable and set your JAVA_HOME environment variable to its root directory.

Flex Builder full installation

The full version installs Eclipse with a JRE that is not affected by the bug referenced above. You should not encounter this problem with this configuration unless you manually changed your configuration to use a different version of JRE. As above, confirm that you are using a JRE/JVM version that is not affected by the referenced bug.


Additional information

When using the Flex Builder Plug-ins to Eclipse to compile your .mxml file, you may see slow compiler performance if you have configured your Eclipse environment to use JRE/JDK version 1.4.2_10 or earlier. For more details regarding the issue, see Suns bug database at and related bugs.

Versions of the 1.5 JRE/JDK before the 06 minor revision have the same problem.

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