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    <p>There is no difference. Any potential difference in terms of memory usage would be optimized by the compiler. </p> <p>If you compile (using <code>javap -c</code>) the two examples and compare the bytecode, you'll find that the bytecode is the same. Of course, this depends on the JVM version. But since this example is so trivial, it's probably safe to assume that neither is more memory efficient than the other.</p> <hr> <h2>Example 1:</h2> <p>Code:</p> <pre><code>public class example1 { public static void main(String[] args) { for (int i=0; i&lt;10; i++) { Object a = new Object(); } } } </code></pre> <p>Bytecode:</p> <pre><code>public class example1 extends java.lang.Object{ public example1(); Code: 0: aload_0 1: invokespecial #1; //Method java/lang/Object."&lt;init&gt;":()V 4: return public static void main(java.lang.String[]); Code: 0: iconst_0 1: istore_1 2: iload_1 3: bipush 10 5: if_icmpge 22 8: new #2; //class java/lang/Object 11: dup 12: invokespecial #1; //Method java/lang/Object."&lt;init&gt;":()V 15: astore_2 16: iinc 1, 1 19: goto 2 22: return } </code></pre> <hr> <h2>Example 2:</h2> <p>Code:</p> <pre><code>public class example2 { public static void main(String[] args) { Object a; for (int i=0; i&lt;10; i++) { a = new Object(); } } } </code></pre> <p>Bytecode:</p> <pre><code>public class example2 extends java.lang.Object{ public example2(); Code: 0: aload_0 1: invokespecial #1; //Method java/lang/Object."&lt;init&gt;":()V 4: return public static void main(java.lang.String[]); Code: 0: iconst_0 1: istore_2 2: iload_2 3: bipush 10 5: if_icmpge 22 8: new #2; //class java/lang/Object 11: dup 12: invokespecial #1; //Method java/lang/Object."&lt;init&gt;":()V 15: astore_1 16: iinc 2, 1 19: goto 2 22: return } </code></pre>
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    1. POMemory Efficiency in Java
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    1. CONow This was quick thinking - Kudos
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    2. COi would prefer the second one (which declares the variable outside of the loop) , so that for debugging i would see the current value of the variable and that it won't become invisible and visible on each loop iteration.
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    3. COJoshua Bloch (author of [*Effective Java*](http://java.sun.com/docs/books/effective/)) would argue otherwise, as described in **Item 45: Minimize the scope of local variables**. :)
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