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How to connect to database through java without creating dsn?
Ashique
- Aug 13th, 2008
Steps Includes:1. Get the URL where the database is exist, get the user name and the password.2. Register the proper database driver.3. Get database connection using DriverManager with the above infor...
vini.rana
- Aug 12th, 2008
We have four types of driverstype1, type2, type3, type4 and we use JDBC and ODBC.We can connect the database b/w two computers using type 3 and 4 drivers. Type 3 and 4 directly calls the native metho...
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Whic is the base class in java, and how it be will the base class
vmshenoy
- Jan 10th, 2007
See the base class(super class) of all classes is Object class.Other wise when u creat a class ,and if that class is inherited by other one, then former one is the base class.bye
abhijith
- Dec 28th, 2006
For a class whichever class you extend becomes its base class..For eg:class SubClass extends BaseClass{}If your class doesn't explicitly "extends" any class then JVM makes Object class as the base cla...
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}
}
public class test1 extends test
{
public void say()
{
super.hello();
hello();
}
public void main(String arg[])
{
test1 t = new test1();
t.say();
}
}
In the above code what will be difference of super.hello(); and hello();. What is use of super instead of calling directly method name.
">Public class test{ public void hello() { System.out.println("Helllo"); }}public class test1 extends test{ public void say(){ super.hello(); hello();}public void main(String arg[]){ test1 t = new test1(); t.say();}}In the above code what will be difference of super.hello(); and hello();. What is use of super instead of calling directly method name.
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Which is the most convient way to create a thread and Why?1) Extends from thread or2) Implements from Runnable Interface.
nkkaushik
- Jan 5th, 2011
Impelementing the Runnable Interface gives a better way to create a Thread because by doing so, you can also extend any other class.
deepthis594
- Dec 27th, 2010
Implementing runnable is the most efficient way to create thread because classes should be extended only when they are being enhanced or modified in some way, while implementing runnable it is only required to override run method.
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Why getInstance() method is used along with class declaration in Java?
komalnk
- Mar 1st, 2016
This is mainly used when there is need of creating an instance of the class.but, when the constructor of class is declared as private. (We cannot create object of object of such class, even inheritance is not possible). So, we use getInstance() method.
sunilbrahmajosyula
- Jan 5th, 2016
It mainly used in singleton class. In the singleton class we will be creating only one object. Where as this getInstance(); will make sure that there is only one copy of an Instance i.e.,copy of an object and returns the single object
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Run Time Exceptions
What do exception mean in java ? what type of run time exceptions?
sanjusr25
- Jun 13th, 2009
Exception means an unwanted condition occur during the excecution of a program.Exception are of two type 1) Checked Exception2) Unchecked Exception Checked exception are those exception which can be...
ranaraj
- Dec 3rd, 2008
List of error exceptions are1).arithmetic Exception2).arrayindexoutofbounds?Exception3).arraystore?Exception4).filenotfoundException 5).ioException6).nullpointerException7).numberformatException8).outofmemoryException9).securityException10).stackoverflowException11).stringindexoutofboundsException
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Nested and Inner Classes
What is the need of nested and inner classes in Java? Explain where they are useful?
Sarje
- Aug 20th, 2009
Using Inner classes you can write more efficient code and even reduce the typing work. Inner classes are frequently used in Event Handling. For example to MouseEvent event is handled in following exam...
msuresh70
- May 23rd, 2009
Nested class is static class wrapped inside the outer classInner class is non-static class wrapped inside the outer class which has access to the instance variables of outer class.
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Which of the following options can be inserted at the commented line to compile the given code:
cpublic class Class1 {
Class1(String s){ }
Class1() { }
}
class Class2 extends Class1{
Class2(){ }
Class2(String s) {super(s);}
void m1() {
// insert code here
}
}
a) Class1 c1 = new Class1("HCL"){ }
b) Class1 c1 = new Class2(){ };
c) Class2 c3 = new Class1(String s){};
d) Class1 c1 = new Class1(100){ }; -
Print Only Numbers From Java Strings
I have a question in Java-string,
String s="adf5hgjyu1frdsff6vgyu7bnjh9asd3"; like
How to print only numbers in that stringVincent
- Jan 11th, 2018
Run someCode() method from main()
Code- span style="color: #0000ff;">"adf5hgjyu1frdsff6vgyu7bnjh9asd3""the number is "+n+" and it is ""Prime""Not Prime""Prime";
- }
rawatfeb
- Feb 23rd, 2016
private static void NumericsFromStringTest() { String alphaNumericString = "h8ll0"; char[] carray = alphaNumericString.toCharArray(); for (char c : carray) { if (Character.isDigit(c)...
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What is the difference between preemptive scheduling and time slicing
Under preemptive scheduling, the highest priority task executes until it enters the waitingor dead states or a higher priority task comes into existence. Under time slicing, a taskexecutes for a predefined slice of time and then reenters the pool of ready tasks. Thescheduler then determines which task should execute next, based on priority andother factors.
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What is the purpose of the finally clause of a try-catch-finally statement
The finally clause is used to provide the capability to execute code no matter whether ornot an exception is thrown or caught.
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What must a class do to implement an interface
It must provide all of the methods in the interface and identify the interface in itsimplements clause.
salembalan
- Feb 15th, 2008
Interface enhance the concepts of inheritence. by calling multiple interfaces to class we can also inherinting more than a class indirectly
Mithun Challa
- Jan 6th, 2008
A class (someName) which wants to use features of the interface(someInterfaceName) must use implements keyword like class someName implements someInterfaceNameIt must define all the methods in t...
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What happens if a try-catch-finally statement does not have a catch clause to handlean exception that is thrown within the body of the try statement
The exception propagates up to the next higher level try-catch statement (if any) orresults in the program's termination.
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What is final variable
Rajesh
- Nov 1st, 2005
Final variable are constants. Once u assigned some value to the final variable,that assigned value througout the ppm is same.u canot modify it.final class cant be inherited.
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What is the difference between Vector, Array and Arraylist
snehakesri
- Mar 20th, 2009
One more point :Vector defaults to doubling the size of its array, while the ArrayList increases its array size by 50 percent.
Sundeep sharma
- Oct 10th, 2006
In Java, arrays are objects. Arrays can be of primitive data types or reference types.
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What is the difference between String and StringBuffer
Rajesh
- Nov 2nd, 2005
String is the immutable we canot modify the string object, whereas StringBuffer is mutable,we can modify the stringobject.perfomance of string is more than the string buffer at runtime.By Rajesh
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What is the difference between HashTable and HashMap?
bhushanamca
- Oct 3rd, 2009
Hashtable does not allow null values or null keys, whereas hash map allows null keys and null values. Hashtable is synchronzied whareas hashmap is not synchronized. In case of single thread using hashmap is faster than the hashtable. In case of multiple thereads, using hashtable is advisable.
Java Interview Questions
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