The amount to add to the local variable is taken from the second byte following the iinc instruction. The local variable and byte are added, and the result is written back to the local variable. This opcode can be used to change a local variable value by any number between and including -128 through 127. This opcode makes for more efficient incrementing and decrementing of variables that are used to control execution of loops, such as for or while. No exceptions are thrown.
Integer subtraction is performed on ints and longs via the following opcodes.
Each opcode causes the top two values of the appropriate type to be popped off the stack. The topmost value is subtracted from the value just beneath the topmost value. The result is pushed back onto the stack. No exceptions are thrown by these opcodes. Each opcode causes two values of the same type to be popped off the stack and multiplied.