NEW YORK — Some Mac users were taken by surprise Thursday as their computers stopped running programs written using the Java programming language after Apple blocked Java due to security problems.

Some Mac users were taken by surprise Thursday as their computers stopped running programs written using the Java programming language after Apple blocked Java due to security problems.

When Apple instituted the first Java block in January the move was considered unusual, in part because Apple has typically used its Xprotect to block malware such as the widespread Flashback ...