/Simple generic class
class A<T>{
T obj;
T get(){
return obj;
}
void set(T o){
obj=o;
}
}
class Gen1{
public static void main(String ar[]){
//Creating object of Generic class
A<Integer> a1;//reference variable declaration
a1=new A<Integer>();//object creation
a1.set(123);//Autoboxing is used to convert int type to Integer type
int i=a1.get();//Auto un-boxing is used to convert Integer type to int type
System.out.println(i);
}
}
//Simple generic class
//with two type-parameters
class A<T,K>{
T obj1;
K obj2;
T getObj1(){
return obj1;
}
void setObj1(T o){
obj1=o;
}
K getObj2(){
return obj2;
}
void setObj2(K o){
obj2=o;
}
}
class Gen1{
public static void main(String ar[]){
A<Integer,String> a1;
a1=new A<Integer,String>();
a1.setObj1(123);
int i=a1.getObj1();
System.out.println(i);
a1.setObj2("This is Test");
String s=a1.getObj2();
System.out.println(s);
}
}
//Simple generic class
//Using type-parameter of user defined class
class X{int x=10;}
class Y{int y=20;}
class Z{int z=30;}
class A<T>{
T obj1;
T getObj1(){
return obj1;
}
void setObj1(T o){
obj1=o;
}
}
class Gen3{
public static void main(String ar[]){
A<X> a1=new A<X>();
a1.setObj1(new X());
X objX=a1.getObj1();
System.out.println(objX.x);
}
}
//Simple generic class
//If type-parameter are super type then object of sub classes can be hold
class X{int x=10;}
class Y extends X{int y=20;}
class Z extends X{int z=30;}
class A<T>{
T obj1;
T getObj1(){
return obj1;
}
void setObj1(T o){
obj1=o;
}
}
class Gen4{
public static void main(String ar[]){
A<X> a1=new A<X>();
a1.setObj1(new Y());
Y o1=(Y)a1.getObj1();
System.out.println(o1.y);
A<Y> a2=new A<Y>();
a2.setObj1(new Y());
Y o2=(Y)a2.getObj1();
System.out.println(o2.y);
/* It will give Error
A<Y> a3=new A<Y>();
a3.setObj1(new X());
X o3=(X)a3.getObj1();
System.out.println(o3.x);*/
}
}
//Simple generic class
//Bounded Type
class X{int x=10;}
class Y extends X{int y=20;}
class Z extends X{int z=30;}
class P {int p=40;}
//Here T can be relaced by X of subclass of X
class A<T extends X>{
T obj1;
T getObj1(){
return obj1;
}
void setObj1(T o){
obj1=o;
}
}
class Gen5{
public static void main(String ar[]){
A<X> a1=new A<X>();
a1.setObj1(new X());
X o1=a1.getObj1();
System.out.println(o1.x);
A<Y> a2=new A<Y>();
a2.setObj1(new Y());
Y o2=a2.getObj1();
System.out.println(o2.y);
//Compile time Error
/*A<P> a3=new A<P>();
a3.setObj1(new P());
P o3=a3.getObj1();
System.out.println(o3.p);*/
}
}
//Simple generic class
//Bounded Type
class X{int x=10;}
class Y extends X{int y=20;}
class Z extends X{int z=30;}
class P {int p=40;}
//Here T can be relaced by X of subclass of X
class A<T extends X>{
T obj1;
T getObj1(){
return obj1;
}
void setObj1(A<?> o){
obj1=o;
}
}
class Gen5{
public static void main(String ar[]){
A<X> a1=new A<X>();
a1.setObj1(new P());
X o1=a1.getObj1();
System.out.println(o1.x);
}
}
//Simple generic class
//Wildcard
class X{int val=10;}
class Y extends X{int val=20;}
class Z extends X{int val=30;}
class P {int val=40;}
//Here T can be relaced by X of subclass of X
class A<T>{
T obj;
A(T o){
obj=o;
}
}
class B{
//this method will take argument of type A,
//but it no need to care about that, what type of type-parameter A class will have
void setObj1(A o){
System.out.println(o.obj.getClass().getName());
}
}
class Gen7{
public static void main(String ar[]){
B b=new B();
A<X> a1=new A<X>(new Y());
b.setObj1(a1);
}
}
//Simple generic class
//Bounded-Wildcard
class X{int val=10;}
class Y extends X{int val=20;}
class Z extends X{int val=30;}
class P {int val=40;}
//Here T can be relaced by X of subclass of X
class A<T>{
T obj;
A(T o){
obj=o;
}
}
class B{
//this method will take argument of type A,
//but it no need to care about that, what type of type-parameter A class will have
//here method will accept type-args of type of X or sub-class X
void setObj1(A<? extends X> o){
System.out.println(o.obj.getClass().getName());
}
}
class Gen8{
public static void main(String ar[]){
B b=new B();
A<Y> a1=new A<Y>(new Y());
b.setObj1(a1);
}
}
//Simple generic Method
class A{
<T>void print(T a)
{
System.out.println("Recieved value : "+a);
}
}
class Gen9{
public static void main(String ar[]){
A a=new A();
a.print(100);
}
}
//Simple generic Method with more type-parameter
class A{
<T,E>void print(T a,E b)
{
System.out.println("Recieved value : "+a);
System.out.println("Recieved value : "+b);
}
}
class Gen10{
public static void main(String ar[]){
A a=new A();
a.print(100,"Strig");
}
}
//Simple generic Method with relation b/w more type-parameter
class A{
<T,E extends T>void print(T a,E b)
{
System.out.println("Recieved value : "+a);
System.out.println("Recieved value : "+b);
}
}
class Gen11{
public static void main(String ar[]){
A a=new A();
//a.print(100,"Strig");
//second arg must of type of first arg or subtype of first arg.
a.print(100,200);
}
}
//Simple generic Method with relation b/w more type-parameter
class x{int val=10;}
class y extends x{int val=10;}
class A{
<T,E extends T>void print(T a,E b)
{
System.out.println("Recieved value : "+a);
System.out.println("Recieved value : "+b);
}
}
class Gen11{
public static void main(String ar[]){
A a=new A();
a.print(new x(),new y());
a.print(new x(),new x());
a.print(new y(),new y());
//a.print(new y(),new x());//Compile time error
}
}
//Simple generic Method with relation b/w more type-parameter
//generic return type
class x{int val=10;}
class y extends x{int val=10;}
class A{
<T,E extends T> T print(E a)
{
T var=a;
return var;
}
}
class Gen13{
public static void main(String ar[]){
A a=new A();
int p=a.print(10);
System.out.println(p);
}
}
//Simple generic constructor
class A{
<E> A(E a)
{
System.out.println(a);
}
}
class Gen14{
public static void main(String ar[]){
A a=new A(1);
}
}
//Generic interface
interface Intf<T>{
void print(T a);
}
class A<T> implements Intf<T>{
public void print(T a){
System.out.println(a);
}
}
class Gen15{
public static void main(String ar[]){
A a=new A();
a.print(10.98);
}
}
//Generic interface
interface Intf<T>{
void print(T a);
}
class A<E extends T> implements Intf<T>{
public void print(T a){
System.out.println(a);
}
}
class Gen15{
public static void main(String ar[]){
A a=new A();
a.print(10.98);
}
}
//Generic subclass and supercalss
class A<T>{
T o;
}
//E is own type-parameter of B and T is for Super class
class B<T,E> extends A<T>{
public void print(T a){
o=a;
System.out.println(a);
}
}
class Gen17{
public static void main(String ar[]){
B a=new B();
a.print(10.98);
}
}
HSQLDB is a portable RDBMS implemented in pure java. It can be embedded with your application as well as can be used separately. It is very a small database that supports almost all features of the standard database system. It comes with small jar file that can be found in lib folder. The HSQLDB jar package is located in the /lib directory of the ZIP package and contains several components and programs. Core components of jar file are : HyperSQL RDBMS Engine (HSQLDB), HyperSQL JDBC Driver, Database Manager, and Sql Tool. Installing and Using Download: download latest release of HyperSQL database from http://hsqldb.org website and extract it. You will see following contents. Here "bin" directory contains some batch files those can be used to run a swing based GUI tool. You can use runManagerSwing.bat to connect to database, but database must be on before running it. Directory lib contains File hsqldb.jar . It is the database to be used by you. Running database First
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