A.It is possible to synchronize static methods.
B.When a thread has yielded as a result of yield（）， it releases its locks.
C.When a thread is sleeping as a result of sleep（）， it releases its locks.
D.The Object.wait（） method can be invoked only from a synchronized context.
E.The Thread.sleep（） method can be invoked only from a synchronized context.
F.When the thread scheduler receives a notify（） request， and notifies a thread， that thread immediately releases its lock.

A.Compilation fails.
B.An exception is thrown at runtime.
C.The code executes normally and prints "foo"；
D.The code executes normally， but nothing is printed.

A.The output could be 5-1，6-1，6-2，5-2
B.The output could be 6-1，6-2，5-1，5-2
C.The output could be 6-1，5-2，6-2，5-1
D.The output could be 6-1，6-2，5-1，7-1

A.4
B.5
C.8
D.9
E.Compilation fails.
F.An exception is thrown at runhime.
G.It is impossible to determine for certain.

A.This code can throw an InterruptedException.
B.This code can throw an IllegalMonitorStateException.
C.This code can throw a TimeoutException after ten minutes.
D.Reversing the order of obj.wait（） and obj.notify（） might cause this method to complete normally.
E.A call to notify（） or notifyAll（） from another thread might cause this method to complete normally.
F.This code does NOT compile unless "obj.wait（）" is replaced with "（（Thread） obj）.wait（）".

A.java.lang.RuntimeException： Problem
B.run.java.lang.RuntimeException： Problem
C.End of method.java.lang.RuntimeException： Problem
D.End of method.run.java.lang.RuntimeException： Problem
E.run.java.lang.RuntimeException： Problem.End of method.

A.Compilation fails.
B.aAaA aAa AAaa AaA
C.AAaa AaA aAa aAaA
D.AaA AAaa aAaA aAa
E.aAa AaA aAaA AAaa
F.An exception is thrown at runtime.

A.Compilation fails.
B.An exception is thrown at runtime.
C.[608， 610， 612， 629] [608， 610]
D.[608， 610， 612， 629] [608， 610， 629]
E.[606， 608， 610， 612， 629] [608， 610]
F.[606， 608， 610， 612， 629] [608， 610， 629]

A.The class implements java.lang.Comparable.
B.The class implements java.util.Comparator.
C.The interface used to implement sorting allows this class to define only one sort sequence.
D.The interface used to implement sorting allows this class to define many different sort sequences.

A.public int hashCode（）
B.public void hashCode（）
C.public int compareTo（Object o）
D.public boolean equals（Object o）
E.public boolean compareTo（Key k）

A.return super.hashCode（）；
B.return name.hashCode（） + age * 7；
C.return name.hashCode（） + comment.hashCode（） / 2；
D.return name.hashCode（） + comment.hashCode（） / 2- age * 3；