Java Garbage Collection Basics and Importance

Are you wondering how garbage collection works in Java? Are you looking for ways to improve your code’s performance? If so, this blog post is for you! In this post, we’ll discuss the basics of garbage collection in Java and why it’s important. We’ll also cover some tips on how to optimize your code and make sure that your code runs efficiently.

Introduction to Java Garbage Collection

Java Garbage Collection is an automated process of memory management that helps Java programs to reclaim unused memory. This process helps to ensure that the program does not need to explicitly mark objects for deletion and can instead rely on the garbage collector to do its job. The garbage collector works by identifying and then removing any unused or unreferenced objects, which ultimately allows for better performance and more efficient use of memory. With the use of garbage collection, designers can focus on coding rather than worrying about memory management.

What is Garbage in Java?

The garbage collector in Java frees up memory space for other objects by reclaiming the memory occupied by garbage objects. Garbage objects are those that are no longer needed or used by the program, and they are stored in the heap after memory allocation. The garbage collector is responsible for freeing up memory once the object becomes garbage. By freeing up this space, it helps to improve the performance of Java applications as well as reduce memory usage.

what is java garbage collector
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How Does Garbage Collection Work?

In Java, garbage collection is the process of managing memory, automatically. It finds unused objects (that are no longer used by the program) and deletes or reclaims them so that the memory can be reused by other objects. The process of garbage collection works by periodically running a special algorithm that searches for unused objects in the application’s memory heap. The garbage collector marks the object for removal when it is no longer in use and releases the memory it settled. Java applications balance creating new objects and disposing of unused ones to maintain efficient resource usage and optimal performance through the garbage collector freeing up memory when it’s needed.

Steps of Garbage Collection

The Steps of Garbage Collection in Java are a complex process that involves multiple steps. First, the garbage collector marks all objects that are no longer used by the program as unreachable. Then, it identifies the unreachable objects and reclaims any memory associated with them. Finally, it compacts the heap memory to reduce fragmentation and optimize the amount of memory available for use. The garbage collector runs continuously in the background, freeing up memory when necessary and optimizing memory usage. By taking these steps, Java programs can ensure they are using resources efficiently and that their performance remains consistent.

The Benefits of Java Garbage Collection

Java garbage collection provides numerous benefits to developers. Automatically freeing up resources for new objects to be created by deallocating memory for objects no longer in use, the garbage collector ensures efficient memory usage and reduces manual memory management code. Garbage collection also simplifies the programming process since developers no longer need to worry about manually allocating and freeing up memory. As a result, they can focus more on writing code that is easy and bug-free. Furthermore, garbage collection helps improve the performance of Java applications by helping reduce the amount of time spent on memory management.

Limitations of Java Garbage Collection

One of the main limitations of Java garbage collection is that it pauses the application threads while performing minor or full GC. This can lead to an increase in latency and cause delays in application performance. Additionally, the garbage collector uses a mark-and-sweep algorithm, which requires the application to mark and compact all the objects before they can be reclaimed. This process can lead to additional overhead on the application and degrade performance. Finally, Designers save time as garbage collection stops the need for manual memory allocation and deallocation. However, this can also lead to memory leaks if not managed properly.

Performance Tuning with the Garbage Collector

When it comes to optimizing Java performance, garbage collection tuning is a critical step. GC tuning is the process of optimizing GC parameters and heap generation sizes to best fit the JVM memory usage at runtime. Reducing latency and increasing application throughput have been proven effective through this process. By optimizing the garbage collection algorithm, developers can take control of their application’s performance and find a balance between garbage collection and application execution. This can improve the overall performance of applications by reducing lag, improving efficiency, and supplying better resource utilization.

The ZGC (Z Garbage Collector)

TJava 11 introduced the experimental Z Garbage Collector (ZGC) implementation. Reduce latency and increase high scalability by concurrently doing heavy lifting work without stopping application threads for more than 10ms. Maximum pause times rarely exceed 250 microseconds, so applications don’t experience long-term pauses. Additionally, Performance tuning can set the number of concurrent garbage collection threads to further optimize performance. ZGC offers a number of benefits that greatly improve the Java garbage collection process and overall application performance.

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Garbage Collection in JDK 14 and Beyond

Many ways have improved Garbage Collection in JDK 14 and beyond. The G1 garbage collector now supports NUMA-aware memory allocations, allowing the JVM to access memory more easily. Additionally, the ZGC (Z Garbage Collector) is an experimental feature on Windows and Linux operating systems, which implements low-latency, pauseless garbage collection. This is beneficial for applications that require quick response times from their JVMs. Furthermore, JDK 14 also includes a number of performance-tuning options for GC performances. Including heap sizing and garbage collection logging. All of these elements can help developers optimize the performance and reliability of their Java applications.


In conclusion, garbage collection is an important part of Java memory management. It helps make Java memory efficient by freeing up space for new objects. And decreasing the need for manual memory management. While garbage collection does have some limitations and can cause application pauses, it is a necessary process for efficient memory management in Java. The Z Garbage Collector and the upcoming JDK 14 further improve garbage collection performance. By understanding how garbage collection works and tuning the garbage collector to meet your application’s needs. You can take advantage of the benefits that garbage collection offers in Java.

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