Bug 164343 [DataBinding] Realm needs consistent Exception handling strategy
bundles/org.eclipse.core.databinding/src/org/eclipse/core/databinding/observable/Realm.java
private static ThreadLocal defaultRealm = new ThreadLocal();
	/**
	 * Returns the default realm for the calling thread, or <code>null</code>
	 * if no default realm has been set.
	 * 
	 * @return the default realm, or <code>null</code>
	 */
	public static Realm getDefault() {
		return (Realm) defaultRealm.get();
	}
	
	/**
	 * Sets the default realm for the calling thread, returning the current
	 * default thread. This method is inherently unsafe, it is recommended to
	 * use {@link #runWithDefault(Realm, Runnable)} instead. This method is
	 * exposed to subclasses to facilitate testing.
	 * 
	 * @param realm
	 *            the new default realm, or <code>null</code>
	 * @return the previous default realm, or <code>null</code>
	 */
	protected static Realm setDefault(Realm realm) {
		Realm oldValue = getDefault();
		defaultRealm.set(realm);
		return oldValue;
	}
	/**