To run JDeveloper 12.2.1.4 successfully, you must adhere to these specific versioning guidelines: JDK 1.8.0_191
Navigate to jdeveloper/jdev/bin/jdev.conf . jdeveloper 12.2.1.4 java version
Standard Oracle JDK (OpenJDK is generally not supported for the installer) ⚠️ The Java 9+ Compatibility Gap To run JDeveloper 12
Since this version of JDeveloper is bundled with Oracle WebLogic Server 12.2.1.4, it inherits the strict JDK 8 requirement of that server runtime. To run JDeveloper 12.2.1.4 successfully
Look for the line starting with SetJavaHome .
Even if your external project targets a newer Java version, the IDE itself must be started using a JDK 8 environment. ⚙️ How to Configure the JDK Path