,JDK / JRE integration in Eclipse

Question

I'm using Eclipse for Java Developers (Keppler) and JDK 8.

While using some Java-7 features like int i = 1_2_3; Eclipse would complain that Java Compliance Level is set to 1.4 . So after browsing through some Stackoverflow threads I would would set it to 1.7 and then after installing the Updates as mentioned here to 1.8.

But I still wonder how does Eclipse use the JDK/JRE or what parts of it does it use to be precise?

And what exactly is the Compliance level ?

How can I control the use of Java by Eclipse like when I want to use specific libraries or switch versions between projects?

Would someone be so kind to provide me with some basic knowledge so that I can understand what this is all about?

Answer 1

The Compliance level is set globally in the workspace, however you can override this at project level, in the Java Compiler pane of the Preferences . It basically sets the version of the generated Java classes, and the Java version you can program against.