It seems that in OpenSUSE both JDK and JRE come together on the same package, unlike Debian which have a separated package for each of them. As I’m not interested on having Java for web, just to use Eclipse every now and then, is there some way to only install development files but not the web plugins (icedtea)?
Not quite.
The JRE is in the packages java-1_8_0-openjdk and java-1_8_0-openjdk-headless, whereas the JDK is in the package java-1_8_0-openjdk-devel.
The browser plugin (IcedTea) is in the package java-1_8_0-openjdk-plugin.
Replace 1_8_0 with 1_7_0 in the package names for Java 1.7.
As I’m not interested on having Java for web, just to use Eclipse every now and then, is there some way to only install development files but not the web plugins (icedtea)?
Yes, just uninstall (or do not install) java-1_X_0-openjdk-plugin.