Small Java trick with copy - paste

Here is a small trick I use to avoid getting into problems.

Some times, I need to copy a block with a variable, for instance:

      Address addr = list.get(0);
      assertEquals("city", "Uppsala", addr.getCity());

and paste it to create something similar like this:

      Address addr2 = person.getAddress()
      assertEquals("city", "Uppsala", addr.getCity());

Did you see the bug?

The trick I use to avoid bugs like this, is to change the variable name in the original block:

      Address addr1 = list.get(0);
      assertEquals("city", "Uppsala", addr1.getCity());
      Address addr2 = person.getAddress()
      assertEquals("city", "Uppsala", addr.getCity());

Then the bug becomes obvious.

I can't tell you how many times this has saved me.