import java.awt.*;
import java.awt.Event.*;
import javax.swing.*;


class aaa
{
int i;
boolean b;
public aaa(int j, boolean c)
{
i=j;
b=c;

j=4;
c=true;
}
}

public class frame4b extends JFrame
{


public frame4b(String titlu)
{
super(titlu);
}

public static void main(String args[])
{
int m=1;
boolean n=false;
frame4b aplicatie = new frame4b("hello");
System.out.println(m+" "+n);
aaa a1 = new aaa(m,n);
m=a1.i;
n=a1.b;
System.out.println(m+" "+n);
aplicatie.setSize(300,300);
aplicatie.show();
}
}

: import java.awt.*;
: import java.awt.Event.*;
: import javax.swing.*;
:
:
: class aaa
: {
: int i;
: boolean b;
: public aaa(int j, boolean c)
: {
: i=j;
: b=c;
:
: j=4;
: c=true;
: }
: }
:
: public class frame4b extends JFrame
: {
:
:
: public frame4b(String titlu)
: {
: super(titlu);
: }
:
: public static void main(String args[])
: {
: int m=1;
: boolean n=false;
: frame4b aplicatie = new frame4b("hello");
: System.out.println(m+" "+n);
: aaa a1 = new aaa(m,n);
: m=a1.i;
: n=a1.b;
: System.out.println(m+" "+n);
: aplicatie.setSize(300,300);
: aplicatie.show();
: }
: }
:
If you are referring to i and b, then they cannot be seen by other classes, because they don't have a public getter/setter method. Here's how your aaa class should look like in "correct" Java:

class Aaa {

     private int i;
     private boolean b;

     public Aaa(int j, boolean c) {
        i = j;
        b = c;
        // The following codes do nothing, because the changes in 
        // j and c are not returned to the caller
        j = 4;
        c = true;
     }

     public int getI() {
        return i;
     }

     public void setI(int i) {
        this.i = i;
     }

     public boolean getB() {
        return b;
     }

     public void setI(boolean i) {
        this.b = b;
     }

}

In your main() you can now get and set the values like this:

      Aaa a1 = new Aaa(m,n);
      m = a1.getI();
      n = a1.getB();
      // Example of set:
      a1.setB(n);