Java is one of the most widely used programming languages and it’s often used by back-end developers as a server-side language. It’s used by über-famous applications like Spotify, Twitter, Signal, and Cash App. Java has evolved immensely over the years and in addition to being easy to write, compile, and debug, it’s also more secure, portable, and effective in memory management compared to other languages. In this blog, we will walk you through the most common Java performance problems and how they can easily be avoided with the help of Java monitoring tools.

Why is Java monitoring vital?

Java performance is highly crucial because any performance hiccup in the application can affect the business and, in turn, its revenue. Researchers have found that with just a 100-millisecond delay in the response time of a page, an e-commerce site could encounter a 7% lower conversion rate. This is where Java performance monitoring comes into play.

A Java performance analyzer analyzes the behavior of your Java application, notifies IT admins or developers instantly about any anomalies, and generates reports periodically based on the performance of the application. You can achieve high performance, prevent costly errors, and deliver a seamless end-user experience with a robust Java performance monitoring tool like ManageEngine Applications Manager.

The most common Java monitoring problems and how to resolve them

The most common Java performance problems are related to the memory, database, concurrency, and code. These problems can be easily avoided and rectified with the help of a Java monitoring tool.

Now, let’s take a look at these problems in depth:

1. Memory leaks and out of memory errors

An out of memory error occurs when you are attempting to add data to the memory but there isn’t enough space for it. Each variable is allocated a certain amount of memory, and when a variable is no longer intended to be used, it has to be flushed. Failure to do so will result in memory leaks. When this occurs in a frequently run code, the Java virtual machine (JVM) exhausts its memory, resulting in the dreaded out of memory error.

Impact: 9/10


With the help of a Java monitoring tool such as Applications Manager, you can obtain data on multiple attributes of memory, like heap, non-heap, and swap memory.

In Java, heap space is utilized to allocate dynamic memory to Java objects at runtime. In heap memory, new items are always produced, and references to these things are kept in stack memory. Non-heap memory refers to all memory allocated by the JVM for purposes apart from the heap. When the RAM is full, swap space is a part of virtual memory on the hard disk drive that is utilized.

By monitoring java metrics such as these, you can view what occupies the most space in the memory and clear unwanted variables from the memory. You can also set a threshold limit for these attributes to be notified of breaches immediately.

Java Monitoring Tool - ManageEngine Applications Manager


2. Thread deadlocks

Java applications are mostly multithreaded. When two or more threads are attempting to access the same resources concurrently, the data pool is locked to ensure that each thread gets exclusive access to the shared JVM resources. A deadlock occurs when one thread locks the resources while other threads wait for the lock to be released. Deadlocks cause the application to slow down or even crash.

Impact: 10/10


To avoid this problem, use Java performance monitoring tools to monitor threads, identify deadlocks, and pinpoint the exact line of code causing the locking so that you can release the locks and resolve the issue.

Java Monitoring - ManageEngine Applications Manager


3. Garbage collection

A garbage collector essentially collects all unwanted data to free up memory space. It may sometimes pause all threads attempting to access the JVM resources to reclaim memory. The frequent occurrence of garbage collection affects performance. When the garbage collector is full, it might result in the application slowing down. For optimal performance, a garbage collector should consume only a small percentage of the CPU’s time (less than 10%). An application will have performance issues connected to memory if the CPU usage by the garbage collector is greater than 20%.

Impact: 8/10


Using Applications Manager’s Java Monitor, you can avoid this problem by setting a threshold for the heap and monitoring the CPU usage, response time, garbage collection time, and other metrics. Excessive garbage collection can hog the CPU and thus interrupt the JVM’s processing, which also affects the performance of the application.

Java Application Monitoring - ManageEngine Applications Manager

4. Code-level issues

All code-level issues should be identified and fixed before an application rollout, but that isn’t always the case. Code-level issues are one of the major factors contributing to performance bottlenecks. These occur due to bugs in the code constructs, such as poor iterations, the improper use of generic templates, inefficient code that causes time complexity, the inability to handle large server loads, a poor choice of data structure, and a lack of proper unit testing.

The consequences of a bug include redundant and misleading outputs. A bug can make a system lose track of its transactions, perform an incorrect transaction, or even refuse to handle a transaction. A bug can also result in the corruption of the database and system failure. Some bugs are not easy to debug, resulting in a lot of wasted development time. Loops that eat up CPU cycles within the JVM are the most common symptom of code-level faults. Bugs affect the performance of an application, so developers have to resolve these problems before the end product hits the market.

Impact: 9/10


Code-level issues can be avoided to an extent by incorporating best practices during the development of the application. The problems that crop up post-development can be isolated using application performance monitoring (APM) solutions. Applications Manager’s core APM feature, named APM Insight, can isolate code-level problems in Java applications in dev, QA, and production environments.


5. Pool connections

Establishing a connection for each data request is expensive, so we use existing pool connections for data transfers. If the number of connections reaches the maximum limit, then the upcoming requests will be put on hold until the existing database requests are completed. If a connection is derived from a particular pool and isn’t later released back into the pool, connection leaks will result, leading to users receiving application errors.

Impact: 8/10


Monitor pool metrics like allocated, free, and managed. Also monitor java performance metrics related to other connections to the database, like the total connection time, active connections, and the health of the database server. This can help you identify the cause of connection leaks.

Java Application Performance Monitoring - ManageEngine Applications Manager

Applications Manager’s Java application monitoring capabilities will help you avoid all of these major Java performance problems. It has guided various businesses around the world in monitoring the performance of their Java applications. If you haven’t used Applications Manager before, you can download a free, 30-day trial or visit our website for a free, live demo and learn how our solution helps you monitor a variety of applications.