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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package sun.awt.util;

A utility class needed to access the root ThreadGroup The class should not depend on any others, because it' called from JNI_OnLoad of the AWT native library. Triggering class loading could lead to a deadlock. /**
 * A utility class needed to access the root {@code ThreadGroup}
 *
 * The class should not depend on any others, because it' called from JNI_OnLoad of the AWT
 * native library. Triggering class loading could lead to a deadlock.
 */
public final class ThreadGroupUtils {

    private ThreadGroupUtils() {
        // Avoid instantiation
    }

    
Returns a root thread group. Should be called with SecurityConstants.MODIFY_THREADGROUP_PERMISSION 
Returns:
a root ThreadGroup/**
     * Returns a root thread group.
     * Should be called with {@link sun.security.util.SecurityConstants#MODIFY_THREADGROUP_PERMISSION}
     *
     * @return a root {@code ThreadGroup}
     */
    public static ThreadGroup getRootThreadGroup() {
        ThreadGroup currentTG = Thread.currentThread().getThreadGroup();
        ThreadGroup parentTG = currentTG.getParent();
        while (parentTG != null) {
            currentTG = parentTG;
            parentTG = currentTG.getParent();
        }
        return currentTG;
    }
}