If you keep on allocating & keeping references to object, you will fill up any amount of memory you have.
One option is to do a transparent file close & open when they switch tabs (you only keep a pointer to the file, and when the user switches tab, you close & clean all the objects… it’ll make the file change slower… but…), and maybe keep only 3 or 4 files on memory.
Other thing you should do is, when the user opens a file, load it, and intercept any OutOfMemoryError, then (as it is not possible to open the file) close that file, clean its objects and warn the user that he should close unused files.
Your idea of dynamically extending virtual memory doesn’t solve the issue, for the machine is limited on resources, so you should be carefull & handle memory issues (or at least, be carefull with them).
A couple of hints i’ve seen with memory leaks is:
—> Keep on mind that if you put something into a collection and afterwards forget about it, you still have a strong reference to it, so nullify the collection, clean it or do something with it… if not you will find a memory leak difficult to find.
—> Maybe, using collections with weak references (weakhashmap…) can help with memory issues, but you must be carefull with it, for you might find that the object you look for has been collected.
—> Another idea i’ve found is to develope a persistent collection that stored on database objects least used and transparently loaded. This would probably be the best approach…
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Если вы словили OutOfMemoryError, то это вовсе не значит, что ваше приложение создает много объектов, которые не могут почиститься сборщиком мусора и заполняют всю память, выделенную вами с помощью параметра -Xmx. Я, как минимум, могу придумать два других случая, когда вы можете увидеть эту ошибку. Дело в том, что память java процесса не ограничивается областью -Xmx, где ваше приложение программно создает объекты.
Область памяти, занимаемая java процессом, состоит из нескольких частей. Тип OutOfMemoryError зависит от того, в какой из них не хватило места.
1. java.lang.OutOfMemoryError: Java heap space
Не хватает место в куче, а именно, в области памяти в которую помещаются объекты, создаваемые программно в вашем приложении. Размер задается параметрами -Xms и -Xmx. Если вы пытаетесь создать объект, а места в куче не осталось, то получаете эту ошибку. Обычно проблема кроется в утечке памяти, коих бывает великое множество, и интернет просто пестрит статьями на эту тему.
2. java.lang.OutOfMemoryError: PermGen space
Данная ошибка возникает при нехватке места в Permanent области, размер которой задается параметрами -XX:PermSize и -XX:MaxPermSize. Что там лежит и как бороться с OutOfMemoryError возникающей там, я уже описал подробнейшим образом тут.
3. java.lang.OutOfMemoryError: GC overhead limit exceeded
Данная ошибка может возникнуть как при переполнении первой, так и второй областей. Связана она с тем, что памяти осталось мало и GC постоянно работает, пытаясь высвободить немного места. Данную ошибку можно отключить с помощью параметра -XX:-UseGCOverheadLimit, но, конечно же, её надо не отключать, а либо решать проблему утечки памяти, либо выделять больше объема, либо менять настройки GC.
4. java.lang.OutOfMemoryError: unable to create new native thread
Впервые я столкнулся с данной ошибкой несколько лет назад, когда занимался нагрузочным тестированием и пытался выяснить максимальное количество пользователей, которые могут работать с нашим веб-приложением. Я использовал специальную тулзу, которая позволяла логинить пользователей и эмулировать их стандартные действия. На определенном количестве клиентов, я начал получать OutOfMemoryError. Не особо вчитываясь в текст сообщения и думая, что мне не хватает памяти на создание сессии пользователя и других необходимых объектов, я увеличил размер кучи приложения (-Xmx). Каково же было мое удивление, когда после этого количество пользователей одновременно работающих с системой только уменьшилось. Давайте подробно разберемся как же такое получилось.
На самом деле это очень просто воспроизвести на windows на 32-битной машине, так как там процессу выделяется не больше 2Гб.
Допустим у вас есть приложение с большим количеством одновременно работающих пользователей, которое запускается с параметрами -Xmx1024M -XX:MaxPermSize=256M -Xss512K. Если всего процессу доступно 2G, то остается свободным еще коло 768M. Именно в данном остатке памяти и создаются стеки потоков. Таким образом, примерно вы можете создать не больше 768*(1024/512)=1536 (у меня при таких параметрах получилось создать 1316) нитей (см. рисунок в начале статьи), после чего вы получите OutOfMemoryError. Если вы увеличиваете -Xmx, то количество потоков, которые вы можете создать соответственно уменьшается. Вариант с уменьшением -Xss, для возможности создания большего количества потоков, не всегда выход, так как, возможно, у вас существуют в системе потоки требующие довольно больших стеков. Например, поток инициализации или какие-нибудь фоновые задачи. Но все же выход есть. Оказывается при программном создании потока, можно указать размер стека: Thread(ThreadGroup group, Runnable target, String name,long stackSize). Таким образом вы можете выставить -Xss довольно маленьким, а действия требующие больших стеков, выполнять в отдельных потоках, созданных с помощью упомянутого выше конструктора.
Более подробно, что же лежит в стеке потока, и куда уходит эта память, можно прочитать тут.
Конечно, вам может показаться данная проблема слегка надуманной, так как большинство серверов нынче крутиться на 64-битной архитектуре, но все же считаю данный пример весьма полезным, так как он помогает разобраться из каких частей состоит память java-процесса.
java.lang.OutOfMemoryError:
Java heap space
Java applications are only allowed to use a limited amount of memory. This limit is specified during application startup. To make things more complex, Java memory is separated into two different regions. These regions are called Heap space and Permgen (for Permanent Generation):
The size of those regions is set during the Java Virtual Machine (JVM) launch and can be customized by specifying JVM parameters -Xmx and -XX:MaxPermSize. If you do not explicitly set the sizes, platform-specific defaults will be used.
The java.lang.OutOfMemoryError: Java heap space error will be triggered when the application attempts to add more data into the heap space area, but there is not enough room for it.
Note that there might be plenty of physical memory available, but the java.lang.OutOfMemoryError: Java heap space error is thrown whenever the JVM reaches the heap size limit.
What is causing it?
There most common reason for the java.lang.OutOfMemoryError: Java heap space error is simple – you try to fit an XXL application into an S-sized Java heap space. That is – the application just requires more Java heap space than available to it to operate normally. Other causes for this OutOfMemoryError message are more complex and are caused by a programming error:
- Spikes in usage/data volume. The application was designed to handle a certain amount of users or a certain amount of data. When the number of users or the volume of data suddenly spikes and crosses that expected threshold, the operation which functioned normally before the spike ceases to operate and triggers the java.lang.OutOfMemoryError: Java heap space error.
- Memory leaks. A particular type of programming error will lead your application to constantly consume more memory. Every time the leaking functionality of the application is used it leaves some objects behind into the Java heap space. Over time the leaked objects consume all of the available Java heap space and trigger the already familiar java.lang.OutOfMemoryError: Java heap space error.
Give me an example
Trivial example
The first example is truly simple – the following Java code tries to allocate an array of 2M integers. When you compile it and launch with 12MB of Java heap space (java -Xmx12m OOM), it fails with the java.lang.OutOfMemoryError: Java heap space message. With 13MB Java heap space the program runs just fine.
class OOM {
static final int SIZE=2*1024*1024;
public static void main(String[] a) {
int[] i = new int[SIZE];
}
}
Memory leak example
The second and a more realistic example is of a memory leak. In Java, when developers create and use new objects e.g. new Integer(5), they don’t have to allocate memory themselves – this is being taken care of by the Java Virtual Machine (JVM). During the life of the application the JVM periodically checks which objects in memory are still being used and which are not. Unused objects can be discarded and the memory reclaimed and reused again. This process is called Garbage Collection. The corresponding module in JVM taking care of the collection is called the Garbage Collector (GC).
Java’s automatic memory management relies on GC to periodically look for unused objects and remove them. Simplifying a bit we can say that a memory leak in Java is a situation where some objects are no longer used by the application but Garbage Collection fails to recognize it. As a result these unused objects remain in Java heap space indefinitely. This pileup will eventually trigger the java.lang.OutOfMemoryError: Java heap space error.
It is fairly easy to construct a Java program that satisfies the definition of a memory leak:
class KeylessEntry {
static class Key {
Integer id;
Key(Integer id) {
this.id = id;
}
@Override
public int hashCode() {
return id.hashCode();
}
}
public static void main(String[] args) {
Map m = new HashMap();
while (true)
for (int i = 0; i < 10000; i++)
if (!m.containsKey(new Key(i)))
m.put(new Key(i), "Number:" + i);
}
}
When you execute the above code above you might expect it to run forever without any problems, assuming that the naive caching solution only expands the underlying Map to 10,000 elements, as beyond that all the keys will already be present in the HashMap. However, in reality the elements will keep being added as the Key class does not contain a proper equals() implementation next to its hashCode().
As a result, over time, with the leaking code constantly used, the “cached” results end up consuming a lot of Java heap space. And when the leaked memory fills all of the available memory in the heap region and Garbage Collection is not able to clean it, the java.lang.OutOfMemoryError:Java heap space is thrown.
The solution would be easy – add the implementation for the equals() method similar to the one below and you will be good to go. But before you manage to find the cause, you will definitely have lose some precious brain cells.
@Override
public boolean equals(Object o) {
boolean response = false;
if (o instanceof Key) {
response = (((Key)o).id).equals(this.id);
}
return response;
}What is the solution?
In some cases, the amount of heap you have allocated to your JVM is just not enough to accommodate the needs of your applications running on that JVM. In that case, you should just allocate more heap – see at the end of this chapter for how to achieve that.
In many cases however, providing more Java heap space will not solve the problem. For example, if your application contains a memory leak, adding more heap will just postpone the java.lang.OutOfMemoryError: Java heap space error. Additionally, increasing the amount of Java heap space also tends to increase the length of GC pauses affecting your application’s throughput or latency.
If you wish to solve the underlying problem with the Java heap space instead of masking the symptoms, you need to figure out which part of your code is responsible for allocating the most memory. In other words, you need to answer these questions:
- Which objects occupy large portions of heap
- where these objects are being allocated in source code
At this point, make sure to clear a couple of days in your calendar (or – see an automated way below the bullet list). Here is a rough process outline that will help you answer the above questions:
- Get security clearance in order to perform a heap dump from your JVM. “Dumps” are basically snapshots of heap contents that you can analyze. These snapshot can thus contain confidential information, such as passwords, credit card numbers etc, so acquiring such a dump might not even be possible for security reasons.
- Get the dump at the right moment. Be prepared to get a few dumps, as when taken at a wrong time, heap dumps contain a significant amount of noise and can be practically useless. On the other hand, every heap dump “freezes” the JVM entirely, so don’t take too many of them or your end users start facing performance issues.
- Find a machine that can load the dump. When your JVM-to-troubleshoot uses for example 8GB of heap, you need a machine with more than 8GB to be able to analyze heap contents. Fire up dump analysis software (we recommend Eclipse MAT, but there are also equally good alternatives available).
- Detect the paths to GC roots of the biggest consumers of heap. We have covered this activity in a separate post here. It is especially tough for beginners, but the practice will make you understand the structure and navigation mechanics.
- Next, you need to figure out where in your source code the potentially hazardous large amount of objects is being allocated. If you have good knowledge of your application’s source code you’ll be able to do this in a couple searches.
Alternatively, we suggest Plumbr, the only Java monitoring solution with automatic root cause detection. Among other performance problems it catches all java.lang.OutOfMemoryErrors and automatically hands you the information about the most memory-hungry data structres.
Plumbr takes care of gathering the necessary data behind the scenes – this includes the relevant data about heap usage (only the object layout graph, no actual data), and also some data that you can’t even find in a heap dump. It also does the necessary data processing for you – on the fly, as soon as the JVM encounters an java.lang.OutOfMemoryError. Here is an example java.lang.OutOfMemoryError incident alert from Plumbr:
Without any additional tooling or analysis you can see:
- Which objects are consuming the most memory (271 com.example.map.impl.PartitionContainer instances consume 173MB out of 248MB total heap)
- Where these objects were allocated (most of them allocated in the MetricManagerImpl class, line 304)
- What is currently referencing these objects (the full reference chain up to GC root)
Equipped with this information you can zoom in to the underlying root cause and make sure the data structures are trimmed down to the levels where they would fit nicely into your memory pools.
However, when your conclusion from memory analysis or from reading the Plumbr report are that memory use is legal and there is nothing to change in the source code, you need to allow your JVM more Java heap space to run properly. In this case, alter your JVM launch configuration and add (or increase the value if present) the following:
-Xmx1024m
The above configuration would give the application 1024MB of Java heap space. You can use g or G for GB, m or M for MB, k or K for KB. For example all of the following are equivalent to saying that the maximum Java heap space is 1GB:
java -Xmx1073741824 com.mycompany.MyClass
java -Xmx1048576k com.mycompany.MyClass
java -Xmx1024m com.mycompany.MyClass
java -Xmx1g com.mycompany.MyClass
How to solve java.lang.outofmemoryerror: java heap space or exception in thread “main”? Know reasons caused by and how to solve it guide.
Introduction
In Java JVM allocates a defined memory size for storing objects created during program execution known as Java Heap Space. Along with it, JVM allocates another memory called PermGen space: permanent generation space.
Java Heap Space
However, we can change the default size with the JVM options.
Most importantly, Oracle completely removed this memory space in the JDK 8 release.
Memory space in the JDK 8 release
Understanding OutOfMemoryError in Java
There most common reason for this error is simple –
If we try to fit a large application into a smaller space. In other words, the application just requires more Java heap space than available to it to operate normally.
Other causes:
- Spikes in usage/data volume- The application was designed to handle a certain amount of users or a certain amount of data. When the number of users or the volume of data suddenly spikes and crosses the expected limit. The operation which functioned normally before the spike ceases to operate and triggers the OutOfMemoryError.
- Memory leaks- A particular type of programming error will lead your application to constantly consume more memory. Every time the leaking functionality of the application is used it leaves some objects behind in the Java heap space. Over time the leaked objects consume all of the available heap space and trigger the already familiar OutOfMemoryError.
Exception in thread “main” java.lang.outofmemoryerror: java heap space
Exception in thread "main" java.lang.OutOfMemoryErrorWhat is causing it?
Generally, bad programming results in OutOfMemoryError. OutOfMemoryError usually means that we’re doing something wrong, either holding onto objects too long or trying to process too much data at a time. Sometimes, it indicates a problem that’s out of our control, such as a third-party library that caches strings, or an application server that doesn’t clean up after deploys.
GC Overhead limit exceeded- This error indicates that the garbage collector is running all the time and the Java program is making very slow progress. If such an event occurs then an OutOfMemoryError is thrown.
Stack vs Java Heap Space
Heap Space
Whenever we create an object, it’s always created in the Heap space.
Stack Memory
Java Stack memory is used for the execution of a thread. It also contains method references.
Note: String Pool is also a part of Java Heap Memory.
Solving java.lang.outofmemoryerror: java heap space error
Increase Java Heap size in Java
The default size of Heap space in Java is 128MB on most of 32 bit Sun’s JVM but it highly varies from JVM to JVM.
For instance, the default maximum and start heap size for the 32-bit Solaris Operating System (SPARC Platform Edition) is -Xms=3670K and -Xmx=64M. And default values of heap size parameters on 64-bit systems have been increased up by approximately 30%.
Also, if we are using a throughput garbage collector in Java 1.5 default maximum heap size of JVM would be Physical Memory/4, and the default initial heap size would be Physical Memory/16.
Another way to find the default heap size of JVM is to start an application with default heap parameters and monitor using JConsole. It is available on JDK 1.5 onwards, on the VMSummary tab, you will be able to see the maximum heap size.
Moreover, we can increase the size of java heap space based on our application need and it is always recommended to avoid using default JVM heap values. Therefore, if our application is large and lots of objects are created. We can change the size of heap space by using JVM options -Xms and -Xmx. Here, Xms denotes the starting size of Heap while -Xmx denotes the maximum size of Heap in Java.
There is another parameter called -Xmn. It denotes the size of the new generation of Java Heap Space. The only thing is we can’t change the size of Heap in Java dynamically. We can only provide the Java Heap Size parameter while starting JVM.
Conclusion
We hope you got your error resolved. Let us know by commenting if you need any help or have any questions.
If this article helped you feel free to share. Keep reading and sharing. Kudos!!
All the applications that you’re trying to execute require memory. It doesn’t matter if the application was developed using assembly language. Or if you used a low-level programming language like C or a language compiled to a bytecode like Java. Running the application requires memory for the code itself, the variables, and the data that the code processes. Depending on your usage, the memory requirements will vary. Some programs will require very little memory – for example, a simple app designed to process small text files; others will require gigabytes of memory because of the amount of data they process in memory.
In Java, at least initially, you can forget about the memory. You create objects, use them and leave them alone. Eventually, the Java garbage collector (GC) will free the memory occupied by unused objects and release the used memory. However, there is always a limited amount of data you can keep in memory at the same time – the size of the heap.
The heap is the place where the Java Virtual Machine keeps the data needed by the application. The heap is not unlimited – you control it during application start and you can’t keep more objects in memory than it allows. If the heap is full and you create that one more object you may receive an OutOfMemory error.
In this blog post, I’ll tell you what Java OutOfMemory errors are, what causes them and how to deal with them.
A java.lang.OutOfMemoryError means that something is wrong in the application – to be precise there was an issue with a part of application memory. To be more specific than that, we need to dive into the reasons that the Java Virtual Machine can go out of memory, and each has a different cause.
Java Heap Space
Java Heap space is one of the most common errors when it comes to memory handling in the Java Virtual Machine world. This error means that you tried to keep too much data on the heap of the JVM process and there is not enough memory to create new objects, and that the garbage collector can’t collect enough garbage. This can happen for various reasons – for example, you may try to load files that are too large into the application memory or you keep the references to the objects even though you don’t need the data.
Basically, the java.lang.OutOfMemoryError Java heap space tells that the heap of your application is not large enough or you are doing something wrong, or you have an old, good Java memory leak.
Here’s an example that illustrates the Java heap space problem:
public class JavaHeapSpace {
public static void main(String[] args) throws Exception {
String[] array = new String[100000 * 100000];
}
}
The code tries to create an array of String objects that is quite large. And that’s it. With the default settings for the memory size, you should see the following result when executing the above code:
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space at memory.JavaHeapSpace.main(JavaHeapSpace.java:5)
And the result is simple – there is just not enough memory on the heap to assign the array, and thus the JVM throws an error informing us about that.
How to fix it: In some cases, to mitigate the problem, it is enough to increase the maximum heap size by adding the -Xmx to your JVM application startup settings and setting it to a larger value. For example, to increase the maximum heap size to 8GB, you would add the -Xmx8g parameter to your JVM application start parameters. However, if you have a memory leak you will eventually see the error appearing again. This means that you need to go through the application code and look for places where potential memory issues can happen. Tools like Java profilers and the good, old heap dump will help you with that.
GC Overhead Limit
The GC Overhead Limit is exactly what its name suggests – a problem with the Java Virtual Machine garbage collector not being able to reclaim memory. You will see the java.lang.OutOfMemoryError: GC overhead limit exceeded if the Java Virtual Machine spends more than 98% of its time in the garbage collection, for 5 consecutive garbage collections and can reclaim less than 2% of the heap.
When using older Java versions that were using the older implementations of the garbage collection (like Java 8), you can easily simulate the GC Overhead exception by running a code similar to the following:
public class GCOverhead {
public static void main(String[] args) throws Exception {
Map<Long, Long> map = new HashMap<>();
for (long i = 0l; i < Long.MAX_VALUE; i++) {
map.put(i, i);
}
}
}
When run with a small heap, like 25MB you would get an exception like this:
Exception in thread "main" java.lang.OutOfMemoryError: GC overhead limit exceeded
at java.base/java.lang.Long.valueOf(Long.java:1211)
at memory.GCOverhead.main(GCOverhead.java:10)
That means that the heap is almost full and the garbage collector spent at least 5 consecutive garbage collections removing less than 2% of the assigned objects.
How to fix it: The possible solution to such an error is increasing the heap by adding the -Xmx to your JVM application startup settings and setting it to a larger value than you are currently using.
Array Size Limits
One of the errors that you may encounter is the java.lang.OutOfMemoryError: Requested array size exceeds VM limit, which points out that the size of the array that you’re trying to keep in memory is larger than the Integer.MAX_INT or that you’re trying to have an array larger than your heap size.
How to fix it: If your array is larger than your heap size, you can try increasing the heap size. If you are trying to put more than the 2^31-1 entries into a single array, you will need to modify your code to avoid such situations.
Number of Thread Issues
The operating system has limits when it comes to the number of threads you can run inside a single application. When you see a java.lang.OutOfMemoryError: unable to create native thread error being thrown by the Java Virtual Machine running your code, you can be sure that you hit the limit or your operating system runs out of resources to create a new thread. Basically, a new thread was not created on the operating system level and the error happened in the Java Native Interface or in the native method itself.
To illustrate the issue with the creation of threads let’s create a code that continuously creates threads and puts them to sleep. For example like this:
public class ThreadsLimits {
public static void main(String[] args) throws Exception {
while (true) {
new Thread(
new Runnable() {
@Override
public void run() {
try {
Thread.sleep(1000 * 60 * 60 * 24);
} catch (Exception ex) {}
}
}
).start();
}
}
}
Right after you run the above code, you can expect an exception thrown:
[0.420s][warning][os,thread] Failed to start thread - pthread_create failed (EAGAIN) for attributes: stacksize: 1024k, guardsize: 4k, detached. Exception in thread "main" java.lang.OutOfMemoryError: unable to create native thread: possibly out of memory or process/resource limits reached at java.base/java.lang.Thread.start0(Native Method) at java.base/java.lang.Thread.start(Thread.java:802) at memory.ThreadsLimits.main(ThreadsLimits.java:15)
We can clearly see that our Java code exhausted the operating system limits and couldn’t create more threads.
To diagnose the issue, we suggest referring to the appropriate section of the Java documentation. For example, Java 17 documentation includes a section called Troubleshooting Tools Based on the Operating System, which mentions tools that can help you find the problem.
PermGen Issues
The PermGen or Permanent Generation is a special place in the Java heap that the Java Virtual Machine uses to keep track of all the loaded classes metadata, static methods, references to static objects, and primitive variables. The PermGen was removed with the release of Java 8, so at this point, you’ll probably never hit the issue with it.
The problem with PermGen was its limited default size – 64MB in 32-bit Java Virtual Machine version and up to 82MB in the 64-bit version of the JVM. This was problematic because if your application contained a lot of classes, static methods, and references to static objects, you could easily get into issues with too small PermGen space.
How to fix it: If you ever encounter the java.lang.OutOfMemoryError: PermGen space error you can start by increasing the size of the PermGen space by including the -XX:PermSize and -XX:MaxPermSize JVM parameters.
Metaspace Issues
With the removal of the PermGen space, the classes metadata now lives in the native space. The space that keeps the classes metadata is now called Metaspace and is part of the Java Virtual Machine heap. However, the region is still limited and can be exhausted if you have a lot of classes.
How to fix it: The problems with the Metaspace region are signaled by the Java Virtual Machine when a java.lang.OutOfMemoryError: Metaspace error is thrown. To mitigate the issue, you can increase the size of the Metaspace by adding the -XX:MaxMetaspaceSize flag to startup parameters of your Java application. For example, to set the Metaspace region size to 128M, you would add the following parameter: -XX:MaxMetaspaceSize=128m.
Out of swap
Your operating system uses the swap space as the secondary memory to handle the memory management scheme’s paging process. When the native memory–both the RAM and the swap–is close to exhaustion, the Java Virtual Machine may not have enough space to create new objects. This may happen for various reasons – your system may be overloaded, other applications may be heavy memory users and are exhausting the resources. In this case the JVM will throw the java.lang.OutOfMemoryError: Out of swap space error, which means that the reason is a problem on the operating system side.
How to fix it: The exact exception stack is usually helpful for mitigatin the error, as it will include the amount of memory that the JVM tried to allocate and the code which did that. When this error occurs, you can expect your Java Virtual Machine to create a file with a detailed description of what happened. You may also want to check your operating system swap settings and increase it if that is too low. At the same time, you need to verify if there are other heavy memory consumers running on the same machine as your application.
How to Catch java.lang.OutOfMemoryError Exceptions
Java has the option to catch exceptions and handle them gracefully. For example, you can catch the FileNotFoundException that can be thrown when trying to work with a file that doesn’t exist. The same can be done with the OutOfMemoryError – you can catch it, but it doesn’t make much sense, at least in most cases. As the developers, we usually can’t do much about the lack of memory in our application. But maybe your specific use-case is such that you would like to do that.
To catch the OutOfMemoryError you just need to surround the code that you expect to cause memory issues with the try-catch block, just like this:
public class JavaHeapSpace {
public static void main(String[] args) throws Exception {
try {
String[] array = new String[100000 * 100000];
} catch (OutOfMemoryError oom) {
System.out.println("OutOfMemory Error appeared");
}
}
}
The execution of the above code, instead of resulting in the OutOfMemoryError will result in printing the following:
OutOfMemory Error appeared
In such a case, you can try recovering from that error, but that is highly use-case dependent. The best solution is to analyze the places where you’re trying to catch the OutOfMemoryError. Definitely avoid catching the mentioned error in the main method where you just start the whole execution. If you don’t know everything about exception handling in Java read our blog post to learn more about how to deal with OutOfMemoryError and other types of Java errors.
Monitor and Analyze Java OutOfMemoryError with Sematext
To ensure a healthy environment for your business process you need to be sure you will not miss any of the errors that can be caused by memory issues when running your Java applications. This means that you need to pay close attention to the logs produced by your Java applications and set up alerting on the relevant events – the OutOfMemoryError ones. You can achieve all of this by using Sematext Logs – an intelligent and easy to use logs centralization solution allowing you to get all the needed information in one place, create alerts and be proactive when dealing with memory issues.
You can read more about Sematext Logs and how it compares with similar solutions in our blog posts about the best log management software, log analysis tools, and cloud logging services available today. Or, if you’d like, check out the short video below to get more familiar with Sematext Logs and how they can help you.
Conclusion
Each memory-related error in Java is different and the approach that we need to take to fix it is different. The first and the most important thing is understanding. To know what needs to be fixed, we need to understand what kind of error happened, when it happened, and finally, why it happened. This information is crucial to take proper reaction and fix the underlying issue that is the root cause of the error.
That is where log management tools, like the Sematext Logs come into play. Having a place where you can see all your exceptions and analyze them is priceless. Sematext Logs is a part of Sematext Cloud, an all-in-one observability solution with Java monitoring integration and JVM Garbage Collector logging capabilities. All of that combined gives you a single platform that allows you to correlate all the necessary metrics. This provides you with a full view of the problem and helps you get to its root cause fast and efficiently. There’s a 14-day free trial available for you to try its features, so give it a try!
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