According to Geoffrey Hodson's book
this is not a deva. He calls it:
An Angel of Java.
On page 237 he states the following:
A remarkable Buddhist Shrine, known as the Borobudur, was built in the Island of Java, some eight hundred years ago. This is an immense stone structure, with scenes from the life of the Lord Buddha beautifully carved on the sides of the four great galleries. This Shrine has become a place of pilgrimage and is regarded by many as a centre of spiritual power. Investigation revealed the presence of a very great presiding Angel, conserver and distributor of the power of the Shrine and source of potent spiritual forces which flow over the island of Java and the surrounding seas.
The height of the central figure is probably from twelve to fifteen feet, but in the case of an Individual, who attained the ascension as a human and then transferred to the Angelic Kingdom, the height of the body is not an indication of spiritual stature.