Based on Bill Verners' Inside the Java Virtual Machine, McGraw Hill Companies, 1997

new - Create a new object
  opcode:  187 (0xbb)
  usage: new class
  stack before: ...
stack after: ..., objectref
description: This instruction creates a new object of the given class descriptor.

newarray - Allocate new array of primitive type components
  opcode:  188 (0xbc)
  usage: newarray type
  stack before: ..., count
stack after: arrayref
description: This instruction pushes on stack a reference to a new array of primitive type components and size count.

nop - Do nothing
  opcode:  0 (0x0)
  usage: nop
  stack: No change
description: This instruction does nothing ;)