Description Sergey Bushkov 2007-02-05 15:32:59 EST

Build ID: 3.2.1.M20060921-0945

Steps To Reproduce:
The source code below is compiled differently by javac (1.5.0_08) and eclipse compiler. The eclipse compiler created two sequental checkcast instructions.

Source code:

package xyz;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;

public class CheckCast {
  private void processLocks(HashMap locksMap, Object key) {
    for (Iterator iter = locksMap.keySet().iterator(); iter.hasNext();) {
      Object call = iter.next();
      List locks = externLocks((Collection) locksMap.get(call), call);
      // ...
    }
  }
  private List externLocks(Collection locks, Object call) {
    List result = new ArrayList();
    // ..
    return result;
  }
}

javac -p -private ... for class compiled with javac:
...
private void processLocks(java.util.HashMap, java.lang.Object);
  Code:
   0:	aload_1
...
   29:	aload	4
   31:	invokevirtual	#6; //Method java/util/HashMap.get:(Ljava/lang/Object;)Ljava/lang/Object;
   34:	checkcast	#7; //class java/util/Collection
   37:	aload	4
...

javac -p -private ... for class compiled with the eclipse compiler:
...
private void processLocks(java.util.HashMap, java.lang.Object);
  Code:
   0:	aload_1
...
   25:	invokevirtual	#34; //Method java/util/HashMap.get:(Ljava/lang/Object;)Ljava/lang/Object;
   28:	checkcast	#38; //class java/util/Collection
   31:	checkcast	#38; //class java/util/Collection
   34:	aload	4
   36:	invokespecial	#40; //Method externLocks:(Ljava/util/Collection;Ljava/lang/Object;)Ljava/util/List;
...

More information:
Default settings are used for project, compiler compliance level 5.0.