title: Unable to use Java in Octave
body: <p>I'm using Octave 4.2.1 on Windows 10. When I type in the Octave console:</p>
  
  <pre><code>&gt;&gt; __have_feature__ JAVA
  ans = 1
  </code></pre>
  
  <p>So java is enabled. Using the Command Prompt on Windows I found that I have java version "1.1.0_71". So java is present and running.
  But when I try to call a java fuction in Octave I get:</p>
  
  <pre><code>cp = javaclasspath
  error: unable to find Java Runtime Environment: software\javasoft\java runtime environment::Currentversion
  </code></pre>
  
  <p>And when I just type 'java -version':</p>
  
  <pre><code>&gt;&gt; java -version
  error: 'java' undefined near line 1 column 1
  </code></pre>
  
  <p>I checked the environment variable for java:</p>
  
  <pre><code>&gt;&gt; getenv JAVA_HOME
  ans = C:\Program Files\Java\jdk1.7.0_71
  </code></pre>
  
  <p>Again, this looks fine. FInally I even tried to install Octave from scratch, but this did not solve the issue. My guess is that it has something to do with the 'software\javasoft\java runtime environment::CurrentVersion' but I'm unable to figure out what it is.</p>