title: Java application CPU/load much higher when built against JDK8
body: <p>I have a Java application developed in Eclipse Luna in Windows that runs in Amazon EC2 (c3.large, Amazon Linux).  This application processes work at a very consistent incoming rate.  When I build the application against JDK 8u31, the EC2 CPU load is much higher than the same application built against JDK 7u75.</p>
  
  <p>The application originally ran with the default JRE on EC2, and I added the OpenJDK 1.8.0.31 to take advantage of the Java 8 Process waitFor(long timeout, TimeUnit unit).  The main work this application does involves invoking an application using Runtime.exec.</p>
  
  <pre><code>$ sudo alternatives --config java
  
  There are 2 programs which provide 'java'.
  
    Selection    Command
  -----------------------------------------------
  *  1           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
   + 2           /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.31-2.b13.5.amzn1.x86_64/jre/bin/java
  </code></pre>
  
  <p>Example load average when the application is built against 1.7:</p>
  
  <pre><code>top - 00:20:28 up 4 days, 10:41,  4 users,  load average: 0.37, 0.26, 0.52
  </code></pre>
  
  <p>Example load average when the application is built against 1.8:</p>
  
  <pre><code>top - 23:45:52 up 4 days, 10:06,  4 users,  load average: 2.28, 2.60, 2.01
  </code></pre>
  
  <p>It seems like it may be related to the Open JDK 1.8.0.31, but I don't know how to debug this.  There are no code changes, I'm only changing the compliance level and build between 1.7 and 1.8 in Eclipse Luna.  Any idea why the load would be so much different?</p>
  
  <p>UPDATE:</p>
  
  <p>I see similar high CPU load when I use the Oracle JDK on EC2.</p>
  
  <pre><code>$ sudo alternatives --config java
  
  There are 3 programs which provide 'java'.
  
    Selection    Command
  -----------------------------------------------
     1           /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java
     2           /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.31-2.b13.5.amzn1.x86_64/jre/bin/java
  *+ 3           /usr/java/jdk1.8.0_31/bin/java
  </code></pre>
  
  <p>Load average:</p>
  
  <pre><code>top - 01:45:27 up 4 days, 12:06,  4 users,  load average: 2.28, 1.50, 1.04
  </code></pre>