What is the difference between shallow copy and deep copy?

Java Interview Questions and Answers (part 1)

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138. What is the difference between shallow copy and deep copy?

Shallow copy shares the same reference with the original object like cloning, whereas the deep copy get a duplicate instance of the original object. If the shallow copy has been changed, the original object will be reflected and vice versa.

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Other Interview Questions

• What's Java?
• What does a well-written OO program look like?
• Can you have virtual functions in Java?
• Jack developed a program by using a Map container to hold key/value pairs. He wanted to make a change to the map. He decided to make a clone of the map in order to save the original data on side. What do you think of it? ?
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• What is NullPointerException and how to handle it?
• An application needs to load a library before it starts to run, how to code??
• How could Java classes direct program messages to the system console, but error messages, say to a file?
• What's the difference between an interface and an abstract class?
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• What do you understand by Synchronization?
• What is Collection API?
• Is Iterator a Class or Interface? What is its use?
• What is similarities/difference between an Abstract class and Interface?
• How to define an Abstract class?
• How to define an Interface?
• If a class is located in a package, what do you need to change in the OS environment to be able to use it?
• How many methods in the Serializable interface?
• How many methods in the Externalizable interface?
• What is the difference between Serializalble and Externalizable interface?
• What is a transient variable?
• Which containers use a border layout as their default layout?
• How are Observer and Observable used?
• What is synchronization and why is it important?
• What are synchronized methods and synchronized statements?
• What are three ways in which a thread can enter the waiting state?
• Can a lock be acquired on a class?
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• What is thread?
• What is multi-threading?
• How does multi-threading take place on a computer with a single CPU?
• How to create a thread in a program?
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• What invokes a thread's run() method?
• What is the purpose of the wait(), notify(), and notifyAll() methods?
• What are the high-level thread states?
• What is the difference between yielding and sleeping?
• What happens when a thread cannot acquire a lock on an object?
• What is the difference between Process and Thread?
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• What is the Vector class?
• What modifiers may be used with an inner class that is a member of an outer class?
• If a method is declared as protected, where may the method be accessed?
• What is an Iterator interface?
• How many bits are used to represent Unicode, ASCII, UTF-16, and UTF-8 characters?
• What's the main difference between a Vector and an ArrayList?
• What are wrapped classes?
• Does garbage collection guarantee that a program will not run out of memory?
• What is the difference between preemptive scheduling and time slicing?
• Name Component subclasses that support painting?
• What is a native method?
• How can you write a loop indefinitely?
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• What is the purpose of finalization?
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• Is the numeric promotion available in other plantform?
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• What is the Properties class?
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• What is the purpose of the System class?
• What is the purpose of the finally clause of a try-catch-finally statement?
• What is the Locale class?
• What is an abstract method?
• What is the difference between interface and abstract class?
• What is a static method?
• What is a protected method?
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• When can an object reference be cast to an interface reference?
• What is the difference between a Window and a Frame?
• What is the difference between a Window and a Frame?
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• What are peerless components?
• What is the difference between the Font and FontMetrics classes?
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• What is the difference between throw and throws keywords?
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• What is the Map interface?
• Does a class inherit the constructors of its superclass?
• Name primitive Java types.
• Which class should you use to obtain design information about an object?
• How can a GUI component handle its own events?
• How are the elements of a GridBagLayout organized?
• What advantage do Java's layout managers provide over traditional windowing systems?
• What are the problems faced by Java programmers who don't use layout managers?
• What is the difference between static and non-static variables?
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• What is the purpose of the File class?
• Why would you use a synchronized block vs. synchronized method?
• What restrictions are placed on method overriding?
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• What class allows you to read objects directly from a stream?
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• How is it possible for two String objects with identical values not to be equal under the == operator? How are this() and super() used with constructors?
• What is an IO filter?
• What is the Set interface?
• How can you force garbage collection?
• What is the purpose of the enableEvents() method?
• What is the difference between the File and RandomAccessFile classes?
• What interface must an object implement before it can be written to a stream as an object?
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• How do you know if an explicit object casting is needed?
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• What are the Object and Class classes used for?
• What is Serialization and deserialization?
• Explain the usage of Java packages.
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• What is polymorphism?
• What is design by contract?
• What are use cases?
• What is scalability and performance?
• What is the benefit of subclass?
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• Where and how can you use a private constuctor.
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