Which is more effective: if (null == variable) or if (variable == null)? [duplicate]

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(Similar to this question: Difference between null==object and object==null)

I would say that there is absolutely no difference in performance between those two expressions.

Interestingly enough however, the compiled bytecode (as emitted by OpenJDKs javac) looks a bit different for the two cases.

For boolean b = variable == null:

 3: aload_1               // load variable
 4: ifnonnull 11          // check if it's null
 7: iconst_1              // push 1
 8: goto 12           
11: iconst_0              // push 0
12: istore_2              // store

For boolean b = null == variable:

 3: aconst_null           // push null
 4: aload_1               // load variable
 5: if_acmpne 12          // check if equal
 8: iconst_1              // push 1
 9: goto 13
12: iconst_0              // push 0
13: istore_2              // store

As @Bozho says, variable == null is the most common, default and preferred style.

For certain situations however, I tend to put the null in front. For instance in the following case:

String line;
while (null != (line = reader.readLine()))
    process(line);

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