Many applications are being written in more than one language to take advantage of the features that different languages provide such as native code support, improved performance, and language-specific libraries. However, there are few static analysis tools currently available to analyze the source code of such multilingual applications. Existing work on cross-language (Java and C/C++) analysis fails to detect cross-language buffer overflow vulnerabilities. In this work, we are addressing how to do cross-language analysis between Java and C/C++. Specifically, we propose an approach to do data flow analysis between Java and C/C++ to detect buffer overflow. We have developed PilaiPidi, a tool that can automatically analyze the data flow in projects written in Java and C/C++. Using our approach, we were able to detect real-world buffer overflow vulnerabilities, which are of cross-language nature, in six different well-known Android applications, and out of these, developers have confirmed 11 vulnerabilities in three applications. This tool is also integrated as a plugin for JetBrains, specifically for IntelliJ IDEA and AndroidStudio, due to its practical usefulness of source code analysis for improving Android application security.