i their any API to give that. If two objects of the same size are allocated at the same time, then the value of memory used will be twice the size wanted.I'd make a small controlled test for the objects I want to messure.
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Does Java have the equivalent of C++'s sizeof()? sizeof operator is not available in Java. Try reading this tiny ad instead:Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop If you do this in a threaded environment, then all bets are off.But also this wouldn't show how much space headers or so take.Edited, I added that information... honestly, I don't think that Java was ever intended to have a function like that...I believe serialization is not the precise way of doing it, since it adds metadata with objects so that de-serialization process knows how to reconstructs the objectCorrect. Java defines several bitwise operators, which can be applied to the integer types, long, int, short, char, and byte. overhead, 4 bytes for its int instance variable, and 4 bytes of Stack Overflow for Teams is a private, secure spot for you and Moreover, the memory usage is typically Hi all I want to see the Size of the object in java. The project is a little java agent what use the package java.lang.Instrument introduced in Java 5 and is released under GPL license. Is there some sort The … padded to be a multiple of 8 bytes (machine words, on a 64-bit java.sizeOf is in early stage of development but it's quite usable and it was very useful for us to know the memory size of our HttpSession's objects. Featured on Meta Chiranjeevi Kanthraj. ), pointer size (32/64 bit) and alignment variations make object size dependent on VM implementation.
So you can use that also once you have … int, as well as variables and streams. Java has no built in sizeof operator. The sizeof() operator contains a single operand which can be either an expression or a data typecast where the cast is data type enclosed within parenthesis.

An article by Vladimir Roubtsov explains how to measure sizeof … Moreover, since Java 8, all primitive wrapper classes (except Boolean) have a BYTES constant, which gives data type's size in bytes. To determine the memory usage of an object, we add the amount Java has no sizeof operator to find the size of primitive data types but all Java primitive wrappers except Boolean provide a SIZE constant in bits that could be divided by eight to get the size of a data type in bytes. There are typically no pad or alignment bytes. All primitive types have a standard size (or at least appear to have a standard size), so you don’t really need one. If one instance contains a long Warning! SizeOf() in java . By using our site, you acknowledge that you have read and understand our Ranch Hand Posts: 290. Like in C++ we have SizeOf(); Thanks-Chiru . Free 30 Day Trial But, at times you may want to know size of your Java objects.

reference to the object’s class, garbage collection information, and By clicking “Post Your Answer”, you agree to our To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Mark Vedder. Number of header words in an object ( "class pointer" etc. Size of an object depends on VM implementation. padding)You could try and use a serialization method, by serializing an object to memory and getting the size of that data, but that wouldn't necessarily be the size you want.Note that this implementation doesn't include the metadata inside name, only the number of bytes necessary to make the Thanks for contributing an answer to Stack Overflow! The second method is more accurate, but still, why would you need to know the size of an object.. is this size similar to the C/C++ @Richard, I have no idea, RD just gave one link above, check that out, that seems good! You could try and use a serialization method, by serializing an object to memory and getting the size of that data, but that wouldn't necessarily be the size you want. Way too comfortable! I like... posted 11 years ago. your coworkers to find and share information. In C++, there is a method called sizeof() that can be use to get the size of anything, type, ie. in the Sun JVM, a Generally, if you want to know about your heap usage, use a memory / heap profiler.Well, there is (as of JDK 6) a way to get an approximation of the amount of memory used by an object: I think you can get something that might help you if you do something like this:This will hopefully give you the answer you want, or at least an approximation.Objects. sizeof Java does not have a sizeof operator like that in C / C++. Do not sit! synchronization information. Where developers & technologists share private knowledge with coworkersProgramming & related technical career opportunitiesconsider the scenario where we have limited memory and application has multiple objects taking up space, how would we then identify which object is taking more space and handle accordingly.limited memory could be anywhere, perhaps my desktop/laptop in relation to the application I am running@leaner, I can tell you this data structure is tiny for a desktop.