java Archives - Page 21 of 22

Difference between sleep(), suspend() and wait() 8

Apr

5

2013

The question that was popped-up to us was what is the difference between suspend(), wait() and sleep() (methods of Java)? Though minute, there is a subtle difference among the three. Here’s how: sleep() is a static method that is used to send the calling thread into a non-runnable state for the given duration of time. The ...

Difference between finally and finalize

Apr

5

2013

finally block is used in exception handling. try { //code that may or may not throw exception, goes here } catch(Exception e) { //handling exception } finally { //Code goes here } The finally block executes after a section of code in a method. For example, if you have code that might ...

Database Connection Pooling 2

Apr

5

2013

In software engineering, a connection pool is a cache of database connections maintained so that the connections can be reused when future requests to the database are required. Connection pools are used to enhance the performance of executing commands on a database. Opening and maintaining a database connection for each user, especially requests made to ...

Daemon Threads

Apr

5

2013

A daemon thread is a thread, that does not prevent the JVM from exiting when the program finishes but the thread is still running. An example for a daemon thread is the garbage collection. Daemon threads are like a service providers for other threads or objects running in the same process as the ...

Constructors and Methods

Apr

5

2013

A constructor is a special method (not appropriate to call it a method but for the sake of analogy) whose task is to initialize the object of its class.It is special because its name is the same as the class name.They do not have return types, not even void and therefore they cannot return values. ...

Comparing java.util.Date with database time (java.sql.Timestamp) 1

Apr

5

2013

And so it happened. I stumbled again and this time I was hit by mere milliseconds. Yeah!!! One sure would find a few milliseconds really insignificant but it gave me a real pain in the a** for a while. All I did was to compare a “cron expression” time (a java.util.Date object) with the timestamp ...

Classloaders – back to basics…

Apr

5

2013

Regular java application running from command line involve three classloaders Bootstrap Classloader It is the parent of all the classloaders and loads the standard JDK classes in the lib directory of JRE (rt.jar and i18n.jar). All the “*. java ” classes are loaded by this loader. Extension Classloader It is the immediate child of bootstrap ...

Class Methods and Instance Methods

Apr

5

2013

S.No. Class Methods Instance Methods 1. Class methods are methods which are declared as static. The method can be called without creating an instance of the class Instance methods on the other hand require an instance of the class to exist before they can be called, so an instance of a class needs to be ...

Characters for formatting a dateTime as String

Apr

5

2013

Source Symbol Meaning Presentation Examples a am or pm marker Text Input am, AM, pm, PM. Output AM or PM d day in month (1-31) Number 1, 20 dd day in month (01-31) Number 01, 31 D day in year (1-366) Number 3, 80, 100 DD day in year (01-366) Number 03, 80, 366 ...

Can we execute a program without main() method in java?

Apr

5

2013

Yes, using static block (not possible from JDK 1.7 onwards) for example: class A { static { String name = getName(); System.out.println(name); } public static String getName() { return “project code bank”; } } output: project code bank Exception in thread “main” java.lang.NoSuchMethodError: main using System.exit(0) in the static we can ...