title: Change java SDK version in maven eclipse project
body: <p>I have created new maven java project in eclipse by clicking <code>File-&gt;New-&gt;Other-&gt;Maven-&gt;New Project</code>. I found that projects is using java 1.5. In my PC exist only java 1.4 and java 8. I need to compile project using java 1.4 JDK. I go to Project->Properties-> JRE System Library and change to java 1.4. When I run main class I have error:</p>
  
  <pre><code>java.lang.UnsupportedClassVersionError: arr/ff (Unsupported major.minor version 49.0)
      at java.lang.ClassLoader.defineClass0(Native Method)
      at java.lang.ClassLoader.defineClass(ClassLoader.java:537)
      at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:251)
      at java.net.URLClassLoader.access$100(URLClassLoader.java:55)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:194)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:187)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:289)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:274)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:235)
      at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:302)
  </code></pre>
  
  <p>How to make project java 1.4 compatible?</p>