Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Server Side Programming Articles
Page 2001 of 2109
Difference between PermGen Space and MetaSpace.
PermGen is the memory area for storing class data like static variable, byte code and etc. By default 64 Mb is allocated for PermGen. It can be tuned by using -XXMaxPermSize.In Java 8, PermGen method area replaced with MetaSpace. They have moved permGem to the separate memory in the native OS and that is called MetaSpace. It can by default auto increases its size. In MetaSpace, classes can load and unload during the lifespan of the JVM.Sr. No.KeyPermGenMetaSpace1BasicPermGen is the memory area for storing class data like static variable, byte code and etcIn Java 8, PermGen method area replaced with ...
Read MoreDifference between Iterator and Spilt Iterator in Java.
Iterator and split iterator both interface are used for iterating over the collection.Split iterator is introduced in Java 8 for achieving parallelism. It can split the given set of element and can perform operation parallely using different independent threads. It can traverse the elements parallely as well as sequentially manner. There are following important methods in the splitIterator interface −trySplit - It is used for split the given set of elements into multiple pieces.tryAdvance - It is equivalent to the hasNext/ next methods available in Iterator interfacegetExactSizeIfKnown -It is used to get the size of the given set of elements.Sr. ...
Read MoreDifference between intermediate and terminal operations in Java 8
Stream is introduced in Java 8, it is only used for processing group of data not for the storting elements.. It does not modify the actual collection, they only provide the result as per the pipelined methods.Stream api supports multiple operations and operations are divided into two parts −Intermediate Operation- These operations are used to pipeline other methods and to transform into the other streams. They don’t produce results because these operation does not invoke until the terminal operation gets executed. Below are the examples −sorted(Comparator)peek(Consumer)distinct()Terminal operations - These operations are used to produce results. They can’t be used for ...
Read MoreDifference between Fixed thread pool and cached thread pool.
Executor framework are designed using thread pool concept. Thread pool is the way to reuse the already created thread instead of creating a new thread every time to execute the current task.Executors class provides a factory method to create thread pools. The ThreadPoolExecutor class is the base implementation for the executors that are returned from many of the Executors factory methods.Sr. No.KeyFixed Thread PoolCached Thread Pool1BasicAs per Java Doc −Creates a thread pool that reuses a fixed number of threads operating off a shared unbounded queue. At any point, at most nThreads threads will be active processing tasks. If additional ...
Read MoreDifference between Executor and ExecutorServices in Java
Executor and ExecutorServices both interfaces are part of the Executor framework. It is released with Java 5. In java, thread creation is very expensive operation so we should reuse the available thread instead of starting a new thread every time and we can achieve the same using Executor framework.Executor framework use the thread pool to execute the task parallel which helps to optimize response time and resource utilization. It provides four types of built in thread pools −Fixed Thread PoolCached Thread PoolScheduled Thread PoolSingle Thread ExecutorSr. No.KeyExecutorExecutorServices1BasicIt is a parent interfaceIt extends Executor Interface2MethodIt has execute() methodIt has submit() method3Return TypeIt ...
Read MoreDifference between Runnable and Callable interface in java
Runnable and Callable both functional interface. Classes which are implementing these interfaces are designed to be executed by another thread.Thread can be started with Ruunable and they are two ways to start a new thread: one is by subclassing Thread class and another is implementing Runnable interface.Thread class does not have constructor for callable so we should use ExecutorService class for executing thread.Sr. No.KeyRunnableCallable1PackageIt belongs to Java.langIt belongs to java.util.concurrent2Thread CreationWe can create thread by passing runnable as a parameter.We can’t create thread by passing callable as parameter 3Return TypeRuunable does not return anythingCallable can return results4.MethodIt has run() methodIt ...
Read MoreDifference between Streams and Collections in Java 8
Java Collections framework is used for storing and manipulating group of data. It is an in-memory data structure and every element in the collection should be computed before it can be added in the collections.Stream API is only used for processing group of data. It does not modify the actual collection, they only provide the result as per the pipelined methods.Sr. No.KeyCollectionsStreams1BasicIt is used for storing and manipulating group of dataStream API is only used for processing group of data2PackageAll the classes and interfaces of this API is in the Java.util packageAll the classes and interfaces of this API is ...
Read MoreHow to create bars with gap among them if there are more categories using ggplot2 in R?
When the number of categories is large in numbers for a variable and we want to create a bar plot then the display of the bar plot becomes a little ambiguous because the bars are plotted very close to each other. To make the bars clearly visible, we can reduce the width of the bars and set different colors for them to make them visually attractive.geom_bar(width=0.2,color="red")Consider the below data frame −x
Read MoreHow to create random sample based on group columns of a data.table in R?
Random sampling helps us to reduce the biasedness in the analysis. If we have data in groups then we might want to find a random sample based on groups. For example, if we have a data frame with a group variable and each group contains ten values then we might want to create a random sample where we will have two values randomly selected from each group. This can be done by using sample function inside .SDExampleConsider the below data.table −library(data.table) Group
Read MoreHow to extract values from an R data frame column that do not start and end with certain characters?
Sometimes we just want to extract the values of a data column based on initial and ending values of a column that has strings or sometimes the values of a column that has strings are recorded with some extra characters and we want to extract those values. For this purpose, we can use negation of grepl with single square brackets.ExampleConsider the below data frame −> x2 df2 head(df2, 20)Outputx2 1 Alabama 2 Alaska 3 American Samoa 4 Arizona 5 Arkansas 6 California 7 Colorado 8 Connecticut 9 Delaware 10 District of Columbia 11 Florida 12 Georgia 13 Guam 14 Hawaii ...
Read More