Example 1
Managing Memory on Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(String[] args) {
int a = 2;
f(a);
System.out.println(a);
}
}
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
main(...)
a
args
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
main(...)
a
2
args
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
?
y
?
x
2
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
?
y
1
x
2
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
?
y
3
x
2
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
10
y
3
x
2
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
10
y
3
x
30
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
10
y
3
x
30
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
f(2)
z
10
y
3
x
30
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
main(...)
a
2
args
...
Stack
public class Test1 {
public static void f(int x) {
int y = 1;
y = x + y;
int z = 10;
x = y * z;
}
public static void main(...) {
int a = 2;
f(a);
System.out.println(a);
}
}
Stack
Example 2
Managing Memory in Heap
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
main(...)
b
?
lt
?
args
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
main(...)
b
?
lt
?
args
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
18540
on
main(...)
false
b
?
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
18540
on
main(...)
false
b
?
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
18540
on
switchOn()
main(...)
true
b
?
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
boolean b;
b = lt.isOn();
System.out.println(b);
}
}
18540
on
main(...)
true
b
true
lt
18540
args
Heap
...
Stack
Example 3
Generating Garbage
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
true
main(...)
lt
args
Heap
18540
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
true
main(...)
18560
on
Heap
lt
false
args
18560
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
true
main(...)
18560
on
Heap
lt
false
args
18560
...
Stack
Example 4
Aliasing
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt2.switchOff();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
true
lt2
?
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt2.switchOff();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
true
lt2
18540
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt2.switchOff();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
false
lt2
18540
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt2.switchOff();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
false
lt2
18540
lt
18540
args
Heap
...
Stack
Example 5
Avoiding Garbage
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
true
lt2
?
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
true
lt2
18540
lt
18540
args
Heap
...
Stack
public class LightProg {
public static void main(...) {
Light lt;
lt = new Light();
lt.switchOn();
Light lt2 = lt;
lt = new Light();
System.out.println(lt.isOn());
}
}
18540
on
main(...)
true
18560
on
Heap
false
lt2
18540
lt
18560
args
...
Stack
Example 6
Allocating Arrays
public class ArrayTest {
public static void main(...) {
int[] array;
array = new int[5];
array[1] = 12;
}
}
main(...)
Heap
array
?
args
...
Stack
public class ArrayTest {
public static void main(...) {
int[] array;
array = new int[5];
array[1] = 8;
}
}
18540
0 0 0 0 0
Heap
main(...)
array
18540
args
...
Stack
public class ArrayTest {
public static void main(...) {
int[] array;
array = new int[5];
array[1] = 8;
}
}
18540
0 8 0 0 0
Heap
main(...)
array
18540
args
...
Stack