How to swap the values of two variables without using a third variable?

In Java, you can swap the values of two variables without using a third variable in several ways.

1. Using arithmetic operations (for numeric types):

int a = 5;
int b = 10;
a = a + b; // a = 15
b = a - b; // b = 5
a = a - b; // a = 10

2. Using bitwise XOR (for integer types):

int a = 5;
int b = 10;
a = a ^ b; // a = 15 (0101 ^ 1010 = 1111)
b = a ^ b; // b = 5  (1111 ^ 1010 = 0101)
a = a ^ b; // a = 10 (1111 ^ 0101 = 1010)

Both methods swap variable values without additional memory. However, be cautious of overflow with arithmetic operations and use them only with appropriate types.