title: How to modify Java/JDK default options?
body: <p>Simple but important:</p>
  
  <ol>
  <li>Where to change default JDK settings of an installed Java per OS (Linux, Windows, Mac) for Oracle or OpenJDK?</li>
  <li>How to see which options are currently set?</li>
  </ol>
  
  <p>Background: Over years of Java development for different systems I have learned there are always some important Java options to be set to get best performance for either system. This might be related to special memory configuration or simply annoying bugs in a special JDK version in combination with a special OS version/graphics configuration and so on.</p>