Proper ThreadLocal usage

ThreadContext.java

import java.util.concurrent.Callable;
import javax.annotation.concurrent.ThreadSafe;

@ThreadSafe
public final class ThreadContext {
  private static final ThreadLocal<Context> CONTEXT = new ThreadLocal<>();
  
  private ThreadContext() {
  }
  
  public static void runInContext(Context context, Runnable runnable) {
    setUp(context);
    try {
      runnable.run();
    } finally {
      tearDown();
    }
  }
  
  public static <T> T callInContext(Context context, Callable<T> callable)
      throws Exception {
    setUp(context);
    try {
      return callable.call();
    } finally {
      tearDown();
    }
  }
  
  private static void setUp(Context context) {
    if (context == null) {
      throw new NullPointerException("context must not be null");
    }
    if (getCurrentContext() != null) {
      throw new IllegalStateException("The context is already set up");
    }
    setCurrentContext(context);
  }
    
  private static void tearDown() {
    if (getCurrentContext() == null) { // Should never happen
      throw new IllegalStateException("The context is already torn down");
    }
    setCurrentContext(null);
  }
  
  public static Context getCurrentContext() {
    return CONTEXT.get();
  }
  
  private static void setCurrentContext(Context context) {
    CONTEXT.set(context);
  }
}

Context.java

public class Context {
}