1. Key Difference 1: Analysis Focus FindBugs is a static analysis tool that focuses on finding potential bugs in Java code. It analyzes the code statically without actually executing it. On the other hand, JaCoCo is a code coverage tool that measures how much of the code is being executed during testing. It tracks the code coverage dynamically by instrumenting the bytecode.

2. Key Difference 2: Detected Issues FindBugs is designed to detect a wide range of potential bugs and issues in the code, including coding errors, misuse of APIs, and other common programming mistakes. It provides a comprehensive analysis of the codebase and highlights areas that could lead to bugs. JaCoCo, on the other hand, does not focus on detecting bugs but instead provides insights into the code coverage achieved during testing.

3. Key Difference 3: Usage in Software Development Lifecycle FindBugs is typically used in the development stage of the software lifecycle to catch potential bugs early in the process. It can be integrated into the build system or used as a standalone tool. JaCoCo, however, is primarily used during the testing phase to measure code coverage. It helps identify areas of the code that are not adequately tested and ensures that test cases cover a significant portion of the code.

4. Key Difference 4: Output Visualization FindBugs provides detailed reports that highlight potential bug patterns in the code. The reports include descriptions of the issues, severity levels, and suggestions for potential fixes. It helps developers understand and address the identified problems. JaCoCo, on the other hand, generates coverage reports that show how each line and branch of the code was covered during testing. These reports help developers assess the effectiveness of their test cases.

5. Key Difference 5: Integration with Build Tools FindBugs can be integrated with various build tools and IDEs, such as Maven and Eclipse, to automate the analysis process. It can be configured to run as part of the build process and provide feedback to developers. On the other hand, JaCoCo can also be integrated into build systems and used alongside test frameworks to measure code coverage during automated testing.

6. Key Difference 6: Execution Context FindBugs analyzes the code statically, meaning it can identify potential bugs without executing the code. This allows it to catch issues that may not be apparent during compilation but could cause problems during runtime. JaCoCo, on the other hand, requires the code to be executed during testing to measure its coverage. It provides insights into the actual execution path of the code.

In summary, FindBugs is a static analysis tool focusing on finding potential bugs in Java code, while JaCoCo is a code coverage tool that tracks the execution of code during testing. FindBugs detects various issues in the code, provides detailed reports, and can be integrated into build systems. JaCoCo measures code coverage, generates coverage reports, and requires the code to be executed during testing.