Found 272 Articles for Java8

Following steps are mostly required to Troubleshoot any problem that occurred in production.As the first step, get the time frame from the user when a particular issue occurred. Get the logs for that particular time period.If logs are very large in size, use grep command to filter out errors.$ grep -o "\w*Exception" error.log | sort -r | uniq -cIt will help to get all the exceptions in error.log sorted in reversed order and give the unique result and with counts.

Following are the areas where Java has proved itself faster than C++.Memory allocation/deallocation: Memory allocation/deallocation is much faster and it is often faster to create a new big array instead of using the cached one.Object instantiation: Memory management done by GC of Java attributes faster object related operations on Java than C++.Multithreading and Synchronization: Modern Java programs makes use of multi-core systems to make synchronization and multithreading much faster operation.JIT has improved a lot over period of time and modern Java program execution now is much faster.String operations are faster by having length. Collection methods are optimized like Array copy.Class loading ... Read More

Modern Java is quite fast and is comparable to C++ code base but it still takes lot of memory. Slowness of Java programs is primarily because of bad programming practices. But following areas are where Java can be improved.Java libraries are written keeping readability and correctness in mind, not performance.Slow String based operations as Strings are UTF-16 encoded objects and are immutable. So more String are used, more memory is required.Boundary checks on arrays also make its operations bit slow.I/O Stream operations are slow considering synchronization checks on each access.Lacking low level functionality like C also attributes to slowness in ... Read More

Java memory model is divided between Thread Stacks (One for each thread) and a heap area.Thread StackIt is a thread specific memory area and contains local variables, methods call information etc. JVM stacks could be of fixed size or variable size. If computation in a thread exceeds its stack size limit then JVM throws StackOverflowError and exits.HeapIt contains all the objects created during application lifecycle. The heap is created when the virtual machine starts up. Garbage collector reclaims heap storage for objects and objects are never explicitly deallocated. The JVM is not using any automatic storage management system, and it ... Read More

JVM has a method area common across all the threads. It contains per-class elements like constant pool, fields, method local data, method code, constructor codes etc. which are used in class and initialization of objects/interfaces.This method area gets created during JVM start-up. It is generally part of Heap area. It could be of fixed size or vary. Its memory may not be contiguous. JVM implementation can give control to programmer over Method area creation, its sizing etc. If method area memory is not sufficient to satisfy an allocation request then JVM throws OutOfMemoryError.

Java memory model is divided between Thread Stacks (One for each thread) and a heap area.Thread Stack: It is a thread specific memory area and contains local variables, methods call information etc. JVM stacks could be of fixed size or variable size. If computation in a thread exceeds its stack size limit then JVM throws StackOverflowError and exits.HeapIt contains all the objects created during application lifecycle. The heap is created when the virtual machine starts up. Garbage collector reclaims heap storage for objects and objects are never explicitly deallocated. The JVM is not using any automatic storage management system, and ... Read More

Execution Engine in Java is the core component of the JVM (java virtual machine) which communicates with different memory areas of the JVM. This component is used to execute the bytecode that is assigned to the runtime data areas via the classloader. In addition to this, each java Class file is executed through the execution engine, and each thread that is present in a running application is a distinct instance of the virtual machine’s execution engine. Hence, by reading this article, you will understand the execution engine in more detail, but before that, let’s comprehend what Java Virtual Machine is. ... Read More

JRE is Java Runtime Environment and is the machine-specific implementation of JVM. It contains libraries like rt.jar, class loaders etc which are used by JVM.

JDK, contains development tools and JRE.

JVM or Java Virtual Machine is a specification to provide the runtime environment on which a bytecode can be executed. JVMs are prepared platform specific and are available for almost all the hardware and machine.Features of JVM −It provides class loader to load a class.It provides bytecode verifier to verify the legality of the bytecode.It provides runtime.It executes the bytecode.