The earliest known writing in Javanese dates from the 4th Century AD, at which time Javanese was written with the Pallava alphabet. By the 10th Century, the Kawi alphabet, which developed from Pallava, had a distinct Javanese form. By the 17th Century, the Javanese alphabet, also known as tjarakan or carakan, had developed into its current form. During the Japanese occupation of Indonesia between 1942 and 1945, the alphabet was prohibited.
For a period from the 15th Century onwards, Javanese was also written with a version of the Arabic alphabet, called pégon or gundil. Since the Dutch introduced the Latin alphabet to Indonesia in the 19th Century, the Javanese alphabet has gradually been supplanted. Today it is used almost exclusively by scholars and for decoration. Those who can read and write it are held in high esteem.
The Javanese alphabet was also used to write Balinese and Sundanese, but has been replaced by the Latin alphabet.
source
wikipedia.org,
omniglot.com &
ethnologue.com