Summary
-------

To match its abstract specification, change the default implementation of `com.sun.management.ThreadMXBean.getCurrentThreadAllocatedBytes`  to return the value of ` getThreadAllocatedBytes(Thread.currentThread().getId())`.

Problem
-------

The existing default implementation of `com.sun.management.ThreadMXBean.getCurrentThreadAllocatedBytes`   is to throw `UnsupportedOperationException`, which is permitted but doesn't match the abstract specification of the method.

Solution
--------

Change the default implementation of `com.sun.management.ThreadMXBean.getCurrentThreadAllocatedBytes`  to return the value of ` getThreadAllocatedBytes(Thread.currentThread().getId())`.

Remove the `@implSpec` portion of the Javadoc that described the throwing of the exception.

Specification
-------------
```
/**
 * Returns an approximation of the total amount of memory, in bytes,
 * allocated in heap memory for the current thread.
 * The returned value is an approximation because some Java virtual machine
 * implementations may use object allocation mechanisms that result in a
 * delay between the time an object is allocated and the time its size is
 * recorded.
 *
 * <p>
 * This is a convenience method for local management use and is
 * equivalent to calling:
 * <blockquote><pre>
 *   {@link #getThreadAllocatedBytes getThreadAllocatedBytes}(Thread.currentThread().getId());
 * </pre></blockquote>
 *
-* @implSpec The default implementation throws
-* {@code UnsupportedOperationException}.
-*
 * @return an approximation of the total memory allocated, in bytes, in
 * heap memory for the current thread
 * if thread memory allocation measurement is enabled;
 * {@code -1} otherwise.
 *
 * @throws java.lang.UnsupportedOperationException if the Java virtual
 *         machine implementation does not support thread memory allocation
 *         measurement.
 *
 * @see #isThreadAllocatedMemorySupported
 * @see #isThreadAllocatedMemoryEnabled
 * @see #setThreadAllocatedMemoryEnabled
 * @since 14
 */
public default long getCurrentThreadAllocatedBytes() {
    return getThreadAllocatedBytes(Thread.currentThread().getId());
}
```