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Core Java - Interview Questions and Answers for 'Declaration' - 16 question(s) found - Order By Newest | ||||
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Ans. It means that the type of variables are checked at compile time in Java.The main advantage here is that all kinds of checking can be done by the compiler and hence will reduce bugs. | ||||
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Like Discuss Correct / Improve  java   statically typed language   variable declaration Asked in 7 Companies basic   frequent | ||||
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Ans. Declaration is intimation to the compiler about the nature of Data a reference is going to hold. For example - List myList; Instantiation is reservation of memory. For example myList = new ArrayList(); Initialization or construction is setting the default values for member elements. For example myList = new ArrayList(mySet); ** Example 2nd is both for instantiation as well as initialization. The only difference is that 2nd will initialized the member elements to their default values whereas 3rd will initialized it with the elements from set. | ||||
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Like Discuss Correct / Improve  declaration   instantiation   initialization   construction   declaration vs instantiation   instantiation vs initialization   declaration vs initialization Asked in 1 Companies basic   frequent | ||||
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Ans. 1st is a valid and standard declaration. 2nd results in compilation error as only 2 dots are there. 3rd results in compilation error as three dots are not consecutive and broken. 4 through 6 may not be standard and ideal way of declarations but they are valid and will compile and work fine. 7 is valid declaration. 8 and 9 will result in compilation error as var args can only be provided to last argument. | ||||
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Like Discuss Correct / Improve  var args  methods  functions   method declaration  scjp  ocjp | ||||
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Ans. First expects the argument as a string array whereas second expects variable number of string arguments or a string array. So we can call both by providing string array as an argument but second can be called with 0 to n string arguments which cannot be done for first. for example - We can call second method with any of following method(); method("Hello"); method("Hello","World"); method(new String[4]); | ||||
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Like Discuss Correct / Improve  var args  methods  method declarations  functions | ||||
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Ans. No. Because java internally treats var args as arrays and hence both method declarations will generate the same byte code and hence would result in ambiguity while determining call binding. | ||||
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Like Discuss Correct / Improve  var args  methods  functions   method declaration  scjp  ocjp | ||||
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Ans. Yes, we can do that. Compiler wont complain. But using object reference we can only access methods which have been defined for object class i.e clone(), equals(), hashCode(), toString() etc. We cannot access methods defined in String class or in any class in hierarchy between String and Object. For example - we cannot do obj.append("abc") as it will now give compile time error. | ||||
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Like Discuss Correct / Improve  object initialization  object declaration   runtime polymorphism  object oriented programming (oops)  oops concepts | ||||
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Ans. Though var args are used rarely but they are pretty useful if a method is expected to receive variable number of arguments. For example - it's pretty useful for the main method as the caller has the flexibility to provide arguments in infinite ways.It provides a convenience and flexibility to the caller. | ||||
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Ans. No Difference. Both are the acceptable ways to declare an array. | ||||
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Like Discuss Correct / Improve  java   array   arrays   array declaration   difference between Asked in 3 Companies basic | ||||
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Ans. Var args is the feature of Java that allows a method to have variable number of arguments. Var args are used when we are not sure about the number of arguments a method may need. Internally java treats them as array. Declarations of methods with var args void method(int... x){}; void method(int x, int... y){}; | ||||
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Like Discuss Correct / Improve  var args  methods  functions   method declaration Asked in 2 Companies | ||||
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Ans. Because var args are not only allowed with the last argument in the method declaration. | ||||
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Ans. No, It will compile and execute perfectly fine. As we are using method with var args , we can call it with 0 to n arguments. | ||||
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Ans. This will compile fine as we can provide 0 arguments for a var arg but will print nothing upon execution. | ||||
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Ans. It will compile fine and the method call will bind to method with specific argument and not with var arg i.e private static void method(String arg) It will print "Hello" upon execution | ||||
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Ans. Yes, it will give compilation error and java will complain about duplicate method. Java treat var args internally as arrays and hence would result in same byte code for both method's syntax. | ||||
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Ans. It won't work as java won't find the method definition for method with 2 arguments. We can either declare the method as private static void method(String arg,String arg2) or private static void method(String... arg) | ||||
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Ans. Yes, but only one of them can be declared public. | ||||
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Like Discuss Correct / Improve  class declaration | ||||