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Answer: Dot notation.
Q.2 The new operator creates a single instance named class and returns a reference to that object.
(a). True
(b). False
Answer: (a). True
(a). True
(b). False
Answer: (a). True
Answer: When an object is no longer referred to by any variable, Java automatically reclaims memory used by that object. This is known as garbage collection.
Answer: Methods are functions that operate on instances of classes in which they are defined.Objects can communicate with each other using methods and can call methods in other classes.
Method definition has four parts. They are name of the method, type of object or primitive type the method returns, a list of parameters and the body of the method. A method's signature is a combination of the first three parts mentioned above.
Answer: Calling methods are similar to calling or referring to an instance variable. These methods are accessed using dot notation.
Ex: bj.methodname(param1,param2)
Answer: Ther is method getClass( ) method in Class class. Which we can can be used to find out what class the belongs to. This class is defined in the object class and is available to all objects.
(a). True
(b). False
Answer: (a). True
Answer: To import a class, the import keyword should be used as shown.
import packagename;
Example:
import java.sql.*;
We are importing here all classes.
import java.sql.Connection ;
In this way we are just importing Connection class here
If we have import sub package then we have do as following :
import r4r.co.in,*;
Answer: Import statement will be very first statements of any class or just before package statement.
Answer: A constructor is a special kind of method that determines how an object is initialized when created.
Answer: new.
Answer: finalize ()
(a). True
(b). False
Answer:(a). True
Answer:Casting is convert the value of one type to another.
(a). True
(b). False
Answer:(a). True
(a). True
(b). False
Answer:(a). True
(a). True
(b). False
Answer:(b). False
(a). True
(b). False
Answer:(a). True
Answer:Explicit cast.
Answer:Specific cast.
(a). The class declaration
(b). The access modifiers
(c). The encapsulation of data & methods with in objects
(d). The use of pointers
Answer:
(a). The class declaration
(b). The access modifiers
(c). The encapsulation of data & methods with in objects
Q.23 Which of the following statements accurately describe the use of access modifiers within a class definition?
(a). They can be applied to both data & methods
(b). They must precede a class's data variables or methods
(c). They can follow a class's data variables or methods
(d). They can appear in any order
(e). They must be applied to data variables first and then to methods
Answer:
(a). They can be applied to both data & methods
(b). They must precede a class's data variables or methods
(d). They can appear in any order
Q.24 Suppose a given instance variable has been declared private. Can this instance variable be manipulated by methods out side its class?
(a). True
(b). False
Answer: (b). False
(a). It is accessible to all other classes in the hierarchy
(b). It is accessible only to subclasses of its parent class
(c). It represents the public interface of its class
(d). The only way to gain access to this method is by calling one of the public class methods
Answer:
(a). It is accessible to all other classes in the hierarchy
(c). It represents the public interface of its class
Q.26 Which of the following types of class members can be part of the internal part of a class?
(a). Public instance variables
(b). Private instance variables
(c). Public methods
(d). Private methods
Answer:
(b). Private instance variables
(d). Private methods
(a). new
(b). dot
Answer: (a). new
Q,28 Which of the following statements correctly describes the relation between an object and the instance variable it stores?
(a). Each new object has its own distinctive set of instance variables.
(b). Each object has a copy of the instance variables of its class.
(c). The instance variable of each object are separate from the variables of other objects.
(d). The instance variables of each object are stored together with the variables of other objects.
Answer:
(a). Each new object has its own distinctive set of instance variables.
(b). Each object has a copy of the instance variables of its class.
(c). The instance variable of each object are separate from the variables of other objects.
Q.29 If no input parameters are specified in a method declaration then the declaration will include __.
(a). An empty set of parentheses
(b). The term void
Answer: (a). An empty set of parentheses
(a). It enables you to access instance variables of any objects within a class
(b). It enables you to store values in instance variables of an object
(c). It is used to call object methods
(d). It is to create a new object
Answer:
(a). It enables you to access instance variables of any objects within a class
(b). It enables you to store values in instance variables of an object
(c). It is used to call object methods
(a). The instance variables of a class only
(b). The methods of a class only
(c). The instance variables and methods of a class
Answer: (c). The instance variables and methods of a class
(a). static
(b). non-static
Answer: (b). non-static
Q.33 Which of the following operators are used in conjunction with the this and super references?
(a). The new operator
(b). The instanceof operator
(c). The dot operator
Answer: (c). The dot operator
(a). True
(b). False
Answer: (a). True
(a). When the default constructor is not called.
(b). When the name of the constructor differs from that of the class.
(c). When there are no constructors for the class.
Answer: (c). When there are no constructors for the class.
(a). True
(b). False
Answer: (a). True
Q.37 When an object is referenced, does this mean that it has been identified by the finalizer method for garbage collection?
(a). True
(b). False
Answer: (b). False
(a). objects
(b). classes
(c). methods
Answer: (b). classes
(a). A class may have only one finalize method
(b). Finalizers are mostly used with simple classes
(c). Finalizer overloading is not allowed
Answer:
(a). A class may have only one finalize method
(c). Finalizer overloading is not allowed
Q.40 When you write finalize() method for your class, you are overriding a finalizer inherited from a super class.
(a). True
(b). False
Answer: (a). True
Q.41 Java memory management mechanism garbage collects objects which are no longer referenced?
(a). True
(b). False
Answer: (a). True
Q.42 are objects referenced by a variable candidates for garbage collection when the variable goes out of scope?
(a). True
(b). False
Answer: (a). True
Q.43 Java's garbage collector runs as a ___ priority thread waiting for __priority threads to relinquish the processor.
(a). high
(b). low
Answer: both
(a). True
(b). False
Answer: (a). True
Q,45 You can explicitly drop a object reference by setting the value of a variable whose data type is a reference type to ___.
Answer: null
(a). before it enters a compute-intense section of code
(b). before it enters a memory-intense section of code
(c). before objects are finalized
(d). when it knows there will be some idle time
Answer:
(a). before it enters a compute-intense section of code
(b). before it enters a memory-intense section of code
(d). when it knows there will be some idle time
Q,47 For externalizable objects the class is solely responsible for the external format of its contents?
(a). True
(b). False
Answer: (a). True
Q.48 When an object is stored, are all of the objects that are reachable from that object stored as well?
(a). True
(b). False
Answer: (a). True
Q.49 The default__ of objects protects private and transient data, and supports the __ of the classes
(a). evolution
(b). encoding
Answer: both
(a). NULL
(b). sizeof
(c). friend
(d). extends
(e). synchronized
Answer:
(d). extends
(e). synchronized
Answer: When class is declared public.
Answer: There are following different modifiers in java:
public, private, protected, default, static, transient, volatile, final, abstract.
Answer: public, private, protected, default.
Answer:
Passing objects: pass by reference
passing primitive values into methods: pass by value
Answer: Yes . A class is a subclass itself.
Answer: public, abstract, final.
(a). Inner class
(b). Anonymous classes
(c). Method overloading
(d). Method overriding
Answer: (c). Method overloading
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