Core Java اسئلة واجوبة المقابلات
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سؤال 121. What is the difference between instanceof and isInstance?
instanceof is used to check to see if an object can be cast into a specified type without throwing a cast class exception. isInstance() Determines if the specified Object is assignment-compatible with the object represented by this Class. This method is the dynamic equivalent of the Java language instanceof operator. The method returns true if the specified Object argument is non-null and can be cast to the reference type represented by this Class object without raising a ClassCastException. It returns false otherwise.
سؤال 122. When can an object reference be cast to an interface reference?
An object reference be cast to an interface reference when the object implements the referenced interface.
سؤال 123. Which class is extended by all other classes?
The Object class is extended by all other classes.
سؤال 124. Does a class inherit the constructors of its superclass?
A class does not inherit constructors from any of its superclasses.
سؤال 125. How would you make a copy of an entire Java object with its state?
Have this class implement Cloneable interface and call its method clone().
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الاكثر فائدة حسب تقييم المستخدمين:
- How could Java classes direct program messages to the system console, but error messages, say to a file?
- What are the differences between an interface and an abstract class?
- Why would you use a synchronized block vs. synchronized method?
- How can you force garbage collection?
- What are the differences between the methods sleep() and wait()?