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  1. PO
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    <p>One of my favorite uses of reflection is the below Java dump method. It takes any object as a parameter and uses the Java reflection API print out every field name and value.</p> <pre><code>import java.lang.reflect.Array; import java.lang.reflect.Field; public static String dump(Object o, int callCount) { callCount++; StringBuffer tabs = new StringBuffer(); for (int k = 0; k &lt; callCount; k++) { tabs.append("\t"); } StringBuffer buffer = new StringBuffer(); Class oClass = o.getClass(); if (oClass.isArray()) { buffer.append("\n"); buffer.append(tabs.toString()); buffer.append("["); for (int i = 0; i &lt; Array.getLength(o); i++) { if (i &lt; 0) buffer.append(","); Object value = Array.get(o, i); if (value.getClass().isPrimitive() || value.getClass() == java.lang.Long.class || value.getClass() == java.lang.String.class || value.getClass() == java.lang.Integer.class || value.getClass() == java.lang.Boolean.class ) { buffer.append(value); } else { buffer.append(dump(value, callCount)); } } buffer.append(tabs.toString()); buffer.append("]\n"); } else { buffer.append("\n"); buffer.append(tabs.toString()); buffer.append("{\n"); while (oClass != null) { Field[] fields = oClass.getDeclaredFields(); for (int i = 0; i &lt; fields.length; i++) { buffer.append(tabs.toString()); fields[i].setAccessible(true); buffer.append(fields[i].getName()); buffer.append("="); try { Object value = fields[i].get(o); if (value != null) { if (value.getClass().isPrimitive() || value.getClass() == java.lang.Long.class || value.getClass() == java.lang.String.class || value.getClass() == java.lang.Integer.class || value.getClass() == java.lang.Boolean.class ) { buffer.append(value); } else { buffer.append(dump(value, callCount)); } } } catch (IllegalAccessException e) { buffer.append(e.getMessage()); } buffer.append("\n"); } oClass = oClass.getSuperclass(); } buffer.append(tabs.toString()); buffer.append("}\n"); } return buffer.toString(); } </code></pre>
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    1. POWhat is reflection and why is it useful?
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    1. USBen Williams
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      1. VTUpMod
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    1. COWhat should Callcount be set to?
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      1. USTom
    2. COI got a Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError when I ran this.
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    3. CO@Tom `callCount` should be set to zero. It's value is used to determine how many tabs should precede each line of output: each time dump needs to dump a "subobject", the output would print as nested in the parent. That method proves useful when wrapped in another. Consider `printDump(Object obj){ System.out.println(dump(obj, 0)); }`.
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