JIL may refer to any of the following:
1. Short for Java Intermediate Language, JIL is a subset of XML that can be used to analyze Java programs to improve performance. It was not adopted on a large scale and is rarely used.
2. Short for Joint Innovation Lab, which is a collaboration among several companies to create mobile services. These companies include Verizon Wireless, Vodafone, China Mobile, and SoftBank Mobile. The venture is also backed by major corporate sponsors, including Samsung Electronics, Research in Motion, Sharp, and LG Electronics.