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copied!<p>If I understood you correctly, you want to know the class (<em>type</em>) of an instance (<em>object</em>) in runtime (<em>existing</em>), which has nothing to do with generics though, as Petr explained.</p> <pre><code>public class Types { public static void main(String[] args) { String s = ""; Runtime r = Runtime.getRuntime(); Types t = new Types(); List<Class> types = new LinkedList<Class>(); types.add(Integer.class); types.add(t.getClass()); types.add(r.getClass()); types.add(s.getClass()); for (Class type :types) { System.out.println(type.getSimpleName()); } } } </code></pre> <p>which outputs:</p> <pre><code>Integer Types Runtime String </code></pre> <p>However, such approach is rarely needed, so rethink is there a simpler solution to your problem. If you still want to tackle it like this:</p> <ul> <li><a href="https://stackoverflow.com/questions/37628/what-is-reflection-and-why-is-it-useful">What is reflection, and why is it useful?</a></li> <li><a href="http://docs.oracle.com/javase/tutorial/reflect/index.html" rel="nofollow noreferrer">official tutorial</a></li> </ul> <p>EDIT:</p> <p>The other interpretation of your question leads to a dynamic generic list as answer:</p> <pre><code>public static <T> List<T> createListOfType() { return new ArrayList<T>(); } public static void main(String[] args) { List<String> a = createListOfType(); List<Integer> b = createListOfType(); a.add(""); b.add(2); a.add(2); // remove this line to compile b.add(""); // remove this line to compile } </code></pre>

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