What is the difference between declaring a variable and defining a variable?

Java Interview Questions and Answers (part 3)

(Continued from previous question...)

493. What is the difference between declaring a variable and defining a variable?

In declaration we just mention the type of the variable and it's name. We do not initialize it. But defining means declaration + initialization.
e.g String s; is just a declaration while String s = new String ("abcd"); Or String s = "abcd"; are both definitions.

(Continued on next question...)

Other Interview Questions

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• What does it mean that a class or member is final?
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• What is the package?
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• 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?
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• How can we make a class Singleton
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• 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?
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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?
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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?
• Difference between Swing and Awt?
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• 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.
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• What is static in java?
• What is final?
• What if the main method is declared as private?
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