title: How can I set a breakpoint in java core class in eclipse?
body: <p>I am using the eclipse3.4.6 and I have attached the src.zip to eclipse. I can successfully view the source code eclipse, but the breakpoint set in java core class dosn't work;
  for example.</p>
  
  <pre><code>HashMap test = new HashMap();
  test.put("a", 0);
  </code></pre>
  
  <p>I can't step into  test.put("a", 0) even if I set a breakpoint in HashMap.class at the begenning of 'put' method.</p>
  
  <p>Thanks in advance.</p>