Java tutorial
//package com.java2s; import java.util.HashMap; import java.util.Map; public class Main { /** * @author TheMrMilchmann * @since DerpieLang v1.0.0 */ @SuppressWarnings("unchecked") public static final <K, V, OK> HashMap<K, V> transform(Map<OK, ?> toTransform) throws IllegalArgumentException { HashMap<K, V> map = new HashMap<K, V>(); try { for (Object key : toTransform.keySet()) { map.put((K) key, (V) toTransform.get((OK) key)); } return map; } catch (Throwable t) { throw new IllegalArgumentException(t); } } }