What if the static modifier is removed from
the signature of the main method? Or What if I do not provide the String array
as the argument to the method?
Program compiles. But at runtime throws an error “NoSuchMethodError”.
Why oracle Type 4 driver is named as oracle
thin driver?
Oracle provides a Type 4 JDBC driver, referred to as the Oracle “thin” driver. This driver includes its own implementation of a TCP/IP version of Oracle’s Net8 written entirely in Java, so it is platform independent, can be downloaded to a browser at runtime, and does not require any Oracle software on the client side. This driver requires a TCP/IP listener on the server side, and the client connection string uses the TCP/IP port address, not the TNSNAMES entry for the database name.
What is the difference between final, finally
and finalize? Or What do you understand by the java
final keyword? Or What is final, finalize() and finally?
Or What is finalize() method? Or What is the difference between final, finally and finalize? Or What does it mean that a class or member is final?
o final -
declare constant
o finally
- handles exception
o finalize
- helps in garbage collection
Variables defined in an interface
are implicitly final. A final class can’t be extended i.e., final class may not
be subclassed. This is done for security reasons with
basic classes like String and Integer. It also allows the compiler to make some
optimizations, and makes thread safety a little easier to achieve. A final
method can’t be overridden when its class is inherited. You can’t change value
of a final variable (is a constant). finalize() method
is used just before an object is destroyed and garbage collected. finally, a key word used in exception handling and will be
executed whether or not an exception is thrown. For example, closing of open
connections is done in the finally method.
What is the Java API?
The Java API is a large
collection of ready-made software components that provide many useful
capabilities, such as graphical user interface (GUI) widgets.
What is the GregorianCalendar
class?
The GregorianCalendar provides support for traditional Western calendars.
What is the ResourceBundle
class?
The ResourceBundle class is used to store locale-specific resources that can be loaded by a program to tailor the program’s appearance to the particular locale in which it is being run.
Why there are no global variables in Java?
Global variables are globally accessible. Java does not support globally accessible variables due to following reasons:
- The global variables breaks the referential
transparency
- Global variables creates collisions in namespace.
How to convert String to Number in java program?
The valueOf() function of Integer class is is
used to convert string to Number. Here is the code example:
String numString = “1000″;
int id=Integer.valueOf(numString).intValue();
What is the SimpleTimeZone class?
The SimpleTimeZone class provides
support for a Gregorian calendar.
What is the difference between a while statement and a do
statement?
A while statement (pre test) checks at the beginning of a loop to
see whether the next loop iteration should occur. A do while statement (post
test) checks at the end of a loop to see whether the next iteration of a loop
should occur. The do statement will always execute the loop body at least once.
What is the Locale class?
The Locale class is used to tailor a program output to the
conventions of a particular geographic, political, or cultural region.
Describe the principles of OOPS.
There are three main principals of oops which are called
Polymorphism, Inheritance and Encapsulation.
Explain the Inheritance principle.
Inheritance is the process by which one object acquires the properties
of another object. Inheritance allows well-tested procedures to be reused and
enables changes to make once and have effect in all relevant places
What is implicit casting?
Implicit casting is the process of simply assigning one entity to
another without any transformation guidance to the compiler. This type of
casting is not permitted in all kinds of transformations and may not work for
all scenarios.
Example
int i =
1000;
long j = i;
//Implicit casting
Is sizeof a keyword in java?
The sizeof operator is not a keyword.
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