The Java Application Monitor (JAMon) is a free, high-performance Java API designed to help developers monitor production applications and identify performance bottlenecks. It provides a simple way to track summary statistics such as execution times, hit counts, and concurrency without significant overhead. Core Functionality
JAMon works by wrapping sections of code with “start” and “stop” methods to gather aggregate data.
Key Metrics Tracked: It automatically calculates hits, total execution time, average, minimum, maximum, standard deviation, and active concurrency for any labeled code block.
MonKeys & Details: Developers can use MonKey objects to pass additional context (like stack traces or method arguments) to monitors, which can be reviewed later in the JAMon web application.
Listeners: JAMon allows you to attach listeners that trigger actions when specific thresholds are met, such as logging an error if a method takes too long. Key Features & Use Cases
Production Monitoring: Designed to be lightweight enough to remain active in production, allowing for real-time performance feedback.
Scalability Testing: Helps determine if an application can handle increased loads by monitoring simultaneous requests and response times.
Broad Compatibility: While built for J2EE/Jakarta EE environments (Servlets, JSPs, EJBs), it works in any JDK 1.2+ environment.
Reporting: Includes a sortable, web-based reporting interface (JAMonAdmin.jsp) to view collected statistics in a human-readable format. Modules & Integration
JAMon includes specialized modules for monitoring various application layers: JDBC: Track database query performance. HTTP: Use Servlet Filters to monitor web requests.
Logging: Integration with libraries like Log4j (though support for newer versions like Log4j2 may require custom appenders).
Distributed Monitoring: Supports cluster integration via tools like Hazelcast. Java performance tuning | PPTX – Slideshare
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