title: java runtime environment no result
body: <p>I am trying to call python within my java code. However I found that if I import numpy in my python code, this is my java code</p>
  <pre><code>Process pcs = Runtime.getRuntime().exec(cmd);
  String result = null;
      
  
  BufferedInputStream in = new BufferedInputStream(pcs.getInputStream());
  BufferedReader br = new BufferedReader(new InputStreamReader(in));        
  System.out.println(&quot;\nExecuting python script file now.&quot;);
  String lineStr = null;
      while ((lineStr = br.readLine()) != null) {
      result = lineStr;
  }
  br.close();
  in.close();
  System.out.println(&quot;done!&quot;);
  System.out.println(result);
  </code></pre>
  <p>This is my python code:</p>
  <pre><code>import sys 
  import os
  import numpy as np
  
  a = sys.argv[1]
  b = sys.argv[2]
  print(&quot;hello world!&quot;)
  print(&quot;%s * %s = %s&quot;%(a,b,int(a)*int(b)))
  </code></pre>
  <p>Results if I don't include &quot;import numpy as np&quot;:
  10 * 11 = 110</p>
  <p>Results if include &quot;import numpy as np&quot;:
  null</p>
  <p>Any intuitive explanation?</p>