[Solved]-Famous "There are no JREs installed in the workspace". Can it do any harm?-eclipse

one potential problem is that your 1.6-targeted code may accidentally use a class or interface that is introduced in jdk1.8. if the jre that is associated with a 1.6 target in your workspace is actually a jre1.8 or 1.7, the code may compile fine but you may end up with something like noclassdeffounderror at runtime.