.add("field2", "value2");
    final String expected = "TestClass{field1=1, value1, field2=value2}";

    assertEquals(expected, helper.toString());
    // Call toString again
    assertEquals(expected, helper.toString());

    // Make sure the cached value is reset when we modify the helper at all
    final String expected2 = "TestClass{field1=1, value1, field2=value2, 2}";
    helper.addValue(2);

Redeclaration does not introduce a new variable; it just assigns a new value to the original.
</p>

<pre>
field1, offset := nextField(str, 0)
field2, offset := nextField(str, offset)  // redeclares offset
a, a := 1, 2                              // illegal: double declaration of a or no new variable if a was declared elsewhere
</pre>

<p>

The non-blank variable names on the left side of <code>:=</code>
must be <a href="#Uniqueness_of_identifiers">unique</a>.
</p>

<pre>
field1, offset := nextField(str, 0)
field2, offset := nextField(str, offset)  // redeclares offset
x, y, x := 1, 2, 3                        // illegal: x repeated on left side of :=
</pre>

<p>
Short variable declarations may appear only inside functions.