Java Questions

- By using method overriding a sub class can change the definition of super class method.

- By using overriding a sub class can modify the functionality of the super class.

DriverManager is a class in java.sql package. It is the basic service for managing a set of JDBC drivers.

A static initializer block is a block of code that declares with the static keyword. It normally contains the block of code that must execute at the time of class loading. The static initializer block will execute only once at the time of loading the class only.

If constructor opens the file 

finalize() method closes that file.

If constructor opens the connection 

finalize() method closes that connection.

To perform finalization operation we must overriding finalize method.

Java applications can call code written in C, C++, or assembler. This is sometimes done for performance and sometimes to access the underlying host operating system or GUI API using the JNI.

The steps for doing that are:

First write the Java code and compile it

Then create a C header file

Create C stubs file

Write the C code

Create shared code library (or DLL)

Run application

SimpleTimeZone is a concrete subclass of TimeZone class. The TimeZone class represents a time zone, that is to be used with Gregorian calendar.

The SimpleTimeZone is created by using the base time zone offset from GMT time zone ID and rules, for starting and ending the time of daylight.

boolean isDirectory();