How to resolve Talend error could not find or load main class

Solution : 

1-Make sure your jdk environment is totally correct.

2- make sure you variable environment are pointing to the right folder ( see capture below )

How to resolve Talend error could not find or load main class

3- try the following commands to check wich jdk env is running on your machine

unix / linux : echo $JAVA_HOME

Windows :

C:\Users\hh>java -version
java version “1.8.0_05”
Java(TM) SE Runtime Environment (build 1.8.0_05-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.5-b02, mixed mode)

4- check if there is any java update that has changes your java env.

Java 8 is currently the recommended Java version for all Talend products and modules since v6.0. Although you can still use Java 7, Java 8 is the only version of Java that is officially supported from Talend v6.0 onwards, due to the end of Oracle support for Java 7.

Prior to v6.0, the recommended Java version was Java 7.

Symptoms

If you are using JDK 1.8 (Java 8) and a Talend product version prior to 6.0, the Studio starts and allows you to create your Jobs. However when executing or exporting a Job, a compilation error appears such as:

Note that the compilation error can occur in various places in the Studio or other Talend applications, as well as at various moments of your development process, depending on your actions.

Resolution

If you are working with a version of Talend prior to v6.0, downgrade the version of Java used to version 7.
Alternatively, upgrade your Talend products to v6.0 or higher that fully supports Java 8.

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