java arraylist example

1. ArrayList Overview: ArrayList is an array queue, which is the equivalent of a dynamic array. Its capacity can grow dynamically compared to an array in Java. It inherits from Abstractlist, implements the list, randomaccess, cloneable, java.io.Serializable these interfaces.ArrayList inherited the Abstractlist and realized the list. It is an array queue that prov

, where only one thread can write vectors at a time, avoiding inconsistencies caused by simultaneous writing of multiple threads, but achieving synchronization requires a high cost, so Accessing it is slower than accessing ArrayList. LinkedList is used to store data in a linked list structure, which is very suitable for the dynamic insertion and deletion of data, and the random access and traversal speed is relatively slow. In addition, he provide

Incompatible type of error collection Package Com.yuanzijian02;import Java.util.arraylist;public class ArrayList2 {public static void main (string[] args) {//T ODO automatically generated method stub ArrayList list = new ArrayList () list.add ("Hello"); List.add (New Integer (2)); String str = (string) list.get (0); String in = (string) list.get (1);}}Execution resultsException in thread "main" Java.la

, where only one thread can write vectors at a time, avoiding inconsistencies caused by simultaneous writing of multiple threads, but achieving synchronization requires a high cost, so Accessing it is slower than accessing ArrayList. LinkedList is used to store data in a linked list structure, which is very suitable for the dynamic insertion and deletion of data, and the random access and traversal speed is relatively slow. In addition, he provide

Translate from: How to Convert arrays to ArrayList in Java?This article analyzes the answer to one of the hottest questions on stack overflow, where the questioner gets a lot of prestige points, allowing him to get the right to do a lot of things on the stack overflow. It has nothing to do with me, let's take a look at it first.The question is "How do I convert an array to

from Destpos to Destpos+length-1. Because it is a native method, it is not visible in the JDK, but you can view the source code in the OPENJDK. The function actually eventually calls the C language's memmove () function, so it can guarantee the correct copying and movement of elements within the same array, which is much more efficient than the general method of replication, and is well suited for batch processing of arrays . Java strongly recommends

Java Container Class Collections ToArray () method, can transform such as arraylist However, the conversion method is wrong. String[] Strarray = (string[]) Arraylist.toarray ();If this execution results in the following error: Exception in thread "XX" java.lang.ClassCastException: [Ljava.lang.Object; cannot being cast to [Ljava.lang.String; The following figure: The correct way should be written: String[

one thread can write vectors at a time, avoiding inconsistencies caused by simultaneous writing of multiple threads, but achieving synchronization requires a high cost, so Accessing it is slower than accessing ArrayList. 3.LinkedList is used to store data in a linked list structure, which is very suitable for the dynamic insertion and deletion of data, and the random access and traversal speed is relatively slow. In addition, he provides methods that

the pointing position. The removal is to move the back forward one bit directly, and the last position is null. From this mode of operation can be seen ArrayList features: for the query, it is very simple, loop array can be, and if you know the subscript, it is possible to directly return the array subscript. However, for the addition of the deletion, if it is in the middle operation, it will involve the movement of the array, it is more troublesome,

of the expansion space).ArrayList and vector The biggest difference is the use of synchronization synchronization,there is no method in ArrayList synchronization , and the majority of vectors are directly or indirectly synchronous , so vectors are thread-safe and ArrayList are not thread -safe, but also because of the vector's thread-safety mechanism, which make

synchronization, where only one thread at a time can write vectors. Avoid inconsistencies caused by multithreading at the same time, but achieving synchronization requires very high costs, so. It is slower to visit than to ask ArrayList.3.LinkedList is used to store data in a linked list structure, which is very suitable for dynamic insertion and deletion of data, and the random access and traversal speed is slower. In addition, he provides methods t

thread can write vectors at a time, avoiding inconsistencies caused by simultaneous writing of multiple threads, but achieving synchronization requires a high cost, so Accessing it is slower than accessing ArrayList.3.LinkedList is used to store data in a linked list structure, which is very suitable for the dynamic insertion and deletion of data, and the random access and traversal speed is relatively slow. In addition, he provides methods that are

Same point: All inherits from Abstractlist and implements the list interface Both Randomaccess and cloneable interfaces are implemented. The default array size is 10 All support iterator traversal Different points: ArrayList is non-thread safe; and vector is thread-safe, its functions are synchronized, that is, all support synchronous Serialization support differs:

Java Collection ArrayList-thoroughly understand additions and deletionsFrom the source to see the initialization and additions and deletions to learn ArrayList.Let's take a look at some of the properties defined by ArrayList:privatestaticfinalint10;privatestaticfinal Object[] EMPTY_ELEMENTDATA = {};privatestaticfinal Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};transient Object[] elementData; // 保存对象pri