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RepreZen Runs on 64-bit Java 8 or Higher 

RepreZen API Studio releases starting with 1.6.15 will install and run on 64-bit Java 8 or higher.  See the Java and Eclipse compatibility matrix for earlier releases of RepreZen API Studio.

If you choose to install a Java release that is available as a JRE (Java Runtime Environment) or a JDK (Java Development Kit), we recommend installing the JDK.

How does API Studio locate Java?

API Studio for Eclipse runs in your Eclipse IDE distribution, which relies on the Eclipse Launcher to locate and instantiate a compatible JVM (Java Virtual Machine). RepreZen API Studio is not involved in this process.

API Studio Desktop releases starting with 1.6.15 detect available Java releases at installation time, and configure API Studio to run with the best available Java version. The installer looks in the standard Java installation directories for your operating system, and will choose among multiple Java installations in the following order: 

  1. Latest available 64-bit JDK, version 8-10 
    JDK is preferred because it facilitates configuration and compilation of custom code generators.
  2. Latest available 64-bit JRE, version 8-10
  3. Latest available 64-bit JDK, version 11
    Java 11 is less preferred because it requires an OSGi configuration change, and API Studio's development features for custom code generation are not currently compatible with Java 11. (See below.)

Once the installer has detected your Java installations and determined the best available version, it will update the reprezen.ini file in the installation folder with a -vm setting to ensure that API Studio runs with that version of Java.

You can manually reconfigure API Studio to run with a different version of Java if needed. See the related article here

Java 11 Compatibility Limitations

API Studio Desktop is built on the Eclipse Oxygen platform. Eclipse Oxygen, in its default configuration, is not compatible with Java 11. If the API Studio installer chooses Java 11 as the best available version, it will add an org.osgi.framework.system.packages setting to the ./configuration/config.ini file under the installation folder, as described here.

Running API Studio with Java 11 in this modified configuration enables all of the essential built-in features. However, it does have some limitations and known implications:

  • API Studio Desktop running with Java 11 is not supported as a development environment for custom code generation. To build custom GenTemplates, we recommend running API Studio Desktop with Java 8, 9, or 10.
  • If you need to run API Studio under a different Java version, we recommend removing the org.osgi.framework.system.packages setting from the ./configuration/config.ini file.

Future releases of RepreZen API Studio will use more recent releases of Eclipse as the target platform, and this should provide full compatibility with Java 11. We are not making this target platform change yet, because it will most likely make API Studio for Eclipse incompatible with one or more currently supported Eclipse IDE distributions.