单项选择题
What happens when thread X executes a wait（） method on object A， without owning object A’s lock？（）
A. Compilation fails.
B. An exception is thrown.
C. The wait（） method has no effect.
D. Thread X receives the lock immediately.
E. Object A moves the thread to the wait pool.
相关考题
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单项选择题
public class SyncTest { private int x； private int y； private synchronized void setX（ int i ） { x = i； } private synchronized void setY（ int i ） { y = i； } public void setXY（ int i ） { setX（i）； setY（i）； } public synchronized boolean check（） { return x != y； } } Under which condition will check return true when called from a different class？ （）
A. check can never return true.
B. check can return true when setXY is called by multiple threads.
C. check can return true when multiple threads call setX and setY separately.
D. check can return true only if SyncTest is changed to allow x and y to be set separately. -
单项选择题
package foo； public class Outer { public static class Inner { } } Which statement is true？（）
A. Compilation fails.
B. An instance of the Inner class can be constructed with “new Outer.Inner（）”.
C. An instance of the Inner class cannot be constructed outside of package foo.
D. An instance of the Inner class can be constructed only from within the Outer class.
E. From within the package foo， and instance of the Inner class can be constructed with “new Inner（）”. -
单项选择题
class A { public A（） { System.out.println（“hello from a”）； } } class B extends A { public B （） { System.out.println（“hello from b”）； super（）； } } public class Test { public static void main（String args[]） { A a = new B（）； } } What is the result when main is executed？（）
A. Compilation fails.
B. hello from a
C. hello from b
D. hello from b hello from a
E. hello from a hello from b
