Note that equal objects must have equal hash codes. Therefore, when overriding the equals method, you must also override the hashCode method. Failure to do so violates the general contract for the hashCode method, and any classes that use the hash code, such as HashMap will not function properly.
In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: 1  electro-magnetic radiation (also known as continuum radiation) Î³ such as radio waves, visible light, and x-rays.
The Electromagnetic Spectrum. The electromagnetic spectrum consists of the full range of known electromagnetic waves, including gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves.All of these are produced by various forms of oscillating charges or currents.amma Rays Gamma rays are the most energetic known form of electromagnetic radiation, with frequencies of 3*10 19 Hz (30 EHz) or higher and wavelengths of 10 -11 m (10 pm) or lower. They are produced from the decay of excited nuclei of radioactive elements.