What is meant by "Abstract Interface"?

Java Interview Questions and Answers (part 3)

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442.. What is meant by "Abstract Interface"?

First, an interface is abstract. That means you cannot have any implementation in an interface. All the methods declared in an interface are abstract methods or signatures of the methods.

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Other Interview Questions

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• Why do threads block on I/O?
• What is synchronization and why is it important?
• Is null a keyword?
• Which characters may be used as the second character of an identifier,but not as the first character of an identifier?
• Whats the difference between notify() and notifyAll()?
• Why can't I say just abs() or sin() instead of Math.abs() and Math.sin()?
• Why are there no global variables in Java?
• What does it mean that a class or member is final?
• What does it mean that a method or class is abstract?
• What is the main difference between Java platform and other platforms?
• What is the Java Virtual Machine?
• What is the Java API?
• What is the package?
• What is native code?
• Explain the user defined Exceptions?
• Is Java code slower than native code?
• Can main() method be overloaded?
• What is the serialization?
• Explain the new Features of JDBC 2.0 Core API?
• Explain garbage collection?
• How you can force the garbage collection?
• What is OOPS?
• Describe the principles of OOPS.
• Explain the Encapsulation principle.
• Explain the Inheritance principle.
• Explain the Polymorphism principle.
• Explain the different forms of Polymorphism.
• What are Access Specifiers available in Java?
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• What are new language features in J2SE 5.0?
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• What are ClassLoaders?
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• What is Session Facade pattern?
• What is Data Access Object pattern?
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• Can we make an EJB singleton?
• How is static Synchronization different form non-static synchronization?
• What are class members and Instance members?
• Name few Garbage collection algorithms?
• Does Java pass by Value or reference?
• Why Thread is faster compare to process?
• When and How is an object considered as Garbage by a GC?
• Can we force Garbage collection?
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• What is a Throughput Collector?
• When to Use the Throughput Collector?
• What is AggressiveHeap?
• What is a Concurrent Low Pause Collector?
• When to Use the Concurrent Low Pause Collector?
• What is Incremental Low Pause Collector?
• When to Use the Incremental Low Pause Collector?
• How do you enable the concurrent garbage collector on Sun's JVM?
• What is a platform?
• What is transient variable?
• How to make a class or a bean serializable?
• What restrictions are placed on method overloading?
• Name Container classes.
• What is the List interface?
• What is the difference between a Scrollbar and a ScrollPane?
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• What is meant by "Abstract Interface"?
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• What is the List interface?
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• What comes to mind when someone mentions a shallow copy in Java?
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• Describe synchronization in respect to multithreading.
• Explain different way of using thread?
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• Difference between HashMap and HashTable?
• Difference between Vector and ArrayList?
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• 470. What is the difference between a constructor and a method?
• What is an Iterator?
• 472. State the significance of public, private, protected, default modifiers both singly and in combination and state the effect of package relationships on declared items qualified by these modifiers.
• What is an abstract class?
• What is static in java?
• What is final?
• What if the main method is declared as private?
• What if the static modifier is removed from the signature of the main method?
• What if I write static public void instead of public static void?
• What if I do not provide the String array as the argument to the method?
• What is the first argument of the String array in main method?
• If I do not provide any arguments on the command line, then the String array of Main method will be empty or null?
• How can one prove that the array is not null but empty using one line of code?
• What environment variables do I need to set on my machine in order to be able to run Java programs?
• Can an application have multiple classes having main method?
• 485. Can I have multiple main methods in the same class?
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• What are Checked and UnChecked Exception?
• What is Overriding?
• What are different types of inner classes?
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• Does importing a package imports the subpackages as well? e.g. Does importing com.MyTest.* also import com.MyTest.UnitTests.*?
• What is the difference between declaring a variable and defining a variable?
• What is the default value of an object reference declared as an instance variable?
• Can a top level class be private or protected?
• What type of parameter passing does Java support?
• Primitive data types are passed by reference or pass by value?
• Objects are passed by value or by reference?
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• How do I serialize an object to a file?
• Which methods of Serializable interface should I implement?
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• 512. What are checked exceptions?
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