title: Does compiling Java with different versions of JDK and same target and source version guaranties same execution?
body: <p>We are going to update our CI system that creates builds from Java 7 to Java 8. Later we would like to migrate projects to Java 8 one by one. Of course, we would like to be able to create bugfix releases for older versions that still use Java 7.</p>
  
  <p>Can we be sure that no issues will appear if we transfer building same source, target version and source version from JDK 7 to JDK 8? We did testing on development machines without any issues.</p>
  
  <p>Before that, we are also gradually updating deployment servers from JRE 7 to JRE 8.</p>
  
  <p>Note that we would like to keep single Java JDK installation on CI system, it gets complicated otherwise.</p>
  
  <p><strong>To make it more clear:</strong>
  I am more interested in same execution outcome, not so much about the same bytecode. Same bytecode would just confirm the first (running on same JRE), if I understand that correctly.</p>
  
  <p>We will not use Java 8 features in code until we have all deployments running on Java 8. So compatibility is not an issue.</p>