Runnable myRunnable = new MyRunnableObject();
new Thread(myRunnable).start();
//синхронизация внутреннего состояния MyRunnableObject по вкусу
new Thread(myRunnable).start();
...

/**
 * A representation of a thread's state. A given thread may only be in one
 * state at a time.
 */
public enum State {
    /**
     * The thread has been created, but has never been started.
     */
    NEW,
    /**
     * The thread may be run.
     */
    RUNNABLE,
    /**
     * The thread is blocked and waiting for a lock.
     */
    BLOCKED,
    /**
     * The thread is waiting.
     */
    WAITING,
    /**
     * The thread is waiting for a specified amount of time.
     */
    TIMED_WAITING,
    /**
     * The thread has been terminated.
     */
    TERMINATED
}

public synchronized void start() {
    /**
     * This method is not invoked for the main method thread or "system"
     * group threads created/set up by the VM. Any new functionality added
     * to this method in the future may have to also be added to the VM.
     *
     * A zero status value corresponds to state "NEW".
     */
    // Android-changed: throw if 'started' is true
    if (threadStatus != 0 || started)
        throw new IllegalThreadStateException();

    /* Notify the group that this thread is about to be started
     * so that it can be added to the group's list of threads
     * and the group's unstarted count can be decremented. */
    group.add(this);

    started = false;
    try {
        nativeCreate(this, stackSize, daemon);
        started = true;
    } finally {
        try {
            if (!started) {
                group.threadStartFailed(this);
            }
        } catch (Throwable ignore) {
            /* do nothing. If start0 threw a Throwable then
              it will be passed up the call stack */
        }
    }
}