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What is the differnce between final, finally and finalize?
What is the differnce between final, finally and finalize? final is used for making a class no-subclassable, and making a member variable as a constant which cannot be modified. finally is usuall used to release all the resources utilized inside the try block. All the resources present in the finali... 2012-09-10, 2647👍, 0💬

In which case would you choose a static inner class?
In which case would you choose a static inner class? Interesting one, static inner classes can access the outer class's protected and private fields. This is both a positive and a negitive point for us since we can, in essence, violate the encapsulation of the outer class by mucking up the outer cla... 2012-09-07, 2479👍, 0💬

What are the different types of inner classes?
What are the different types of inner classes? There are four different types of inner classes in Java. They are: a)Static member classes , a static member class has access to all static methods of the parent, or top-level, class b) Member classes, the member class is instance specific and has acces... 2012-09-07, 2503👍, 0💬

Can you call one constructor from another if a class has multiple constructors?
Can you call one constructor from another if a class has multiple constructors? Yes. Use this() syntax. 2012-09-06, 2940👍, 0💬

How to check two arrays to see if contents have the same types and contain the same elements?
How to check two arrays to see if contents have the same types and contain the same elements? One of options is to use the equals() method of Arrays class. Arrays.equals(a, b); If the array types are different, a compile-time error will happen. 2012-09-06, 2426👍, 0💬

When is the ArrayStoreException thrown?
When is the ArrayStoreException thrown? When copying elements between different arrays, if the source or destination arguments are not arrays or their types are not compatible, an ArrayStoreException will be thrown. 2012-09-05, 2447👍, 0💬

What is shallow copy or shallow clone in array cloning?
What is shallow copy or shallow clone in array cloning? Cloning an array invloves creating a new array of the same size and type and copying all the old elements into the new array. But such copy is called shallow copy or shallow clone because any changes to the object would be reflected in both arr... 2012-09-05, 2490👍, 0💬

Can we use System.arraycopy() method to copy the same array?
Can we use System.arraycopy() method to copy the same array? Yes, you can. The source and destination arrays can be the same if you want to copy a subset of the array to another area within that array. 2012-09-04, 2672👍, 0💬

How to make an array copy from System?
How to make an array copy from System? There is a method called arraycopy in the System class. You can do it: System.arraycopy(sourceArray, srcOffset, destinationArray, destOffset, numOfElements2Copy); When you use this method, the destinationArray will be filled with the elements of sourceArray at ... 2012-09-04, 2558👍, 0💬

What kind of security tools are available in J2SE 5.0?
What kind of security tools are available in J2SE 5.0? There are three tools that can be used to protect application working within the scope of security policies set at remote sites. keytool -- used to manage keystores and certificates. jarsigner -- used to generate and verify JAR signatures. polic... 2012-09-03, 2566👍, 0💬

What is the difference between final, finally and finalize?
What is the difference between final, finally and finalize? Short answer: final - declares constant finally - relates with exception handling finalize - helps in garbage collection If asked to give details, explain: final field, final method, final class try/finally, try/catch/finally protected void... 2012-09-03, 2690👍, 0💬

Why Java does not support multiple inheritance ?
Why Java does not support multiple inheritance ? This is a classic question. Yes or No depends on how you look at Java. If you focus on the syntax of "extends" and compare with C++, you may answer 'No' and give explanation to support you. Or you may answer 'Yes'. Recommend you to say 'Yes'. Java DOE... 2012-08-31, 2589👍, 0💬

Can a private method of a superclass be declared within a subclass?
Can a private method of a superclass be declared within a subclass? Sure. A private field or method or inner class belongs to its declared class and hides from its subclasses. There is no way for private stuff to have a runtime overloading or overriding (polymorphism) features. 2012-08-31, 2316👍, 0💬

How do you create a read-only collection?
How do you create a read-only collection? The Collections class has six methods to help out here: 1. unmodifiableCollection(Collect ionc) 2. unmodifiableList(List list) 3. unmodifiableMap(Map m) 4. unmodifiableSet(Set s) 5. unmodifiableSortedMap(SortedMa pm) 6. unmodifiableSortedSet(SortedSe ts) If ... 2012-08-30, 2475👍, 0💬

Two methods have key words static synchronized and synchronized separately. What is the difference between them?
Two methods have key words static synchronized and synchronized separately. What is the difference between them? Both are synchronized methods. One is instance method, the other is class method. Method with static modifier is a class method. That means the method belongs to class itself and can be a... 2012-08-30, 2515👍, 0💬

Is there any other way that you can achieve inheritance in Java?
Is there any other way that you can achieve inheritance in Java? There are a couple of ways. As you know, the straight way is to "extends" and/or "implements". The other way is to get an instance of the class to achieve the inheritance. That means to make the supposed-super-class be a field member. ... 2012-08-29, 2462👍, 0💬

What are the drawbacks of inheritance?
What are the drawbacks of inheritance? Since inheritance inherits everything from the super class and interface, it may make the subclass too clustering and sometimes error-prone when dynamic overriding or dynamic overloading in some situation. In addition, the inheritance may make peers hardly unde... 2012-08-29, 2620👍, 0💬

This class (IncrementImpl) will be used by various threads concurrently; can you see the inherent flaw(s)? How would you improve
This class (IncrementImpl) will be used by various threads concurrently; can you see the inherent flaw(s)? How would you improve it? public class IncrementImpl { private static int counter = 0; public synchronized void increment() { counter++; } public int getCounter() { return counter; } } The coun... 2012-08-28, 2464👍, 0💬

What is the relationship between synchronized and volatile keyword?
What is the relationship between synchronized and volatile keyword? The JVM is guaranteed to treat reads and writes of data of 32 bits or less as atomic.(Some JVM might treat reads and writes of data of 64 bits or less as atomic in future) For long or double variable, programmers should take care in... 2012-08-28, 2898👍, 0💬

What's the difference between constructors and other methods?
What's the difference between constructors and other methods? Constructors must have the same name as the class and can not return a value. They are only called once while regular methods could be called many times. 2012-08-27, 2516👍, 0💬

Why is multiple inheritance not possible in Java?
Why is multiple inheritance not possible in Java? It depends on how you understand "inheritance". Java can only "extends" one super class, but can "implements" many interfaces; that doesn't mean the multiple inheritance is not possible. You may use interfaces to make inheritance work for you. Or you... 2012-08-27, 2582👍, 0💬

Can one create a method which gets a String and modifies it?
Can one create a method which gets a String and modifies it? No. In Java, Strings are constant or immutable; their values cannot be changed after they are created, but they can be shared. Once you change a string, you actually create a new object. For example: String s = "abc"; //create a new String... 2012-08-24, 2438👍, 0💬

What is the difference between shallow copy and deep copy?
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. 2012-08-24, 2518👍, 0💬

Can you declare a class as private?
Can you declare a class as private? Yes, we can declare a private class as an inner class. For example, class MyPrivate { private static class MyKey { String key = "12345"; } public static void main(String[] args) { System.out.println(new MyKey().key);//prints 12345 } } 2012-08-23, 2743👍, 0💬

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.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML