The amount of coding in Java Applications has increased over the years, which necessitates the understanding of the behavior of Java Applications at runtime to evaluate performance. Because of this growth in coding within Java Applications, computer scientists have been increasingly interested in correlating execution data and performance. Collection of execution data about a running Java Application is referred to as Tracing. Tracing the Java code execution is most effectively done by source code instrumentation and bytecode instrumentation. This project illustrates the use of ExecTracer as a bytecode instrumentation tool to trace Java code execution. ExecTracer uses the ASM bytecode manipulation framework to manipulate bytecode and Java Agent is used to perform on the fly bytecode manipulation, otherwise known as Dynamic Instrumentation. Java Agent utilizes the Instrumentation Application Program Interface (API) that provides alteration for the existing bytecode loaded in the Java Virtual Machine (JVM). ExecTracer performs Instrumentation on the running Java Application and logs execution trace information. Trace results from ExecTracer on several Java Applications shows excellent accuracy about instructions executed, execution frequency, and percentage coverage. The execution trace information provided by ExecTracer can be used for code coverage analysis during testing phase or for monitoring the performance of the Java Application after deployment, thereby aiding in selecting better code refactoring techniques and reduce code complexity.