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First, let's talk about the differences among final, finally, and finalize. Second, can Anonymous Inner Class (Anonymous internal Class) be extends (inherited) other classes, or implements (implemented) interface (interface )? Third, the difference between Static Nested Class and Inner Class is that the more you say, the better (the more general the interview questions are ). Fourth, the difference between
Let's talk about some questions about the java programmer interview.
This blog post is intended for recent graduates and java programmers who have been working for about two or three years.
Why do I need to change jobs?
This is a broad question. Everyone has an answer.
For example:
The company is not well-treated,
The
The following content is the original Java surface of the online question set and the answer after a comprehensive revision of the responsible questions and answers, the original topic has a lot of repetitive topics and worthless topics, there are many reference answers is also wrong, modified
dispatch and dispatch, and a smaller unit that can run independently than a process. Thread's StrokeThe sub-scale is less than the process, which makes the multi-threaded procedure highly concurrency, and the process typically has independent memory units at execution time, while the threads can share memory. Programming with multithreading often leads to better performance and user experience,But multithreaded programs are unfriendly to other programs because they may consume more CPU resource
separately, which belongs to the salvage function operation.Interview question: Please explain the difference between ArrayList and Vector.· These two classes are subclasses of the List interface;· The Vector class is provided at JDK 1.0, and the method of operation provided is synchronous, so it is thread-safeThe Operation class;· The ArrayList class is provided at JDK 1.2, and the method provided is asynchronous, so it belongs to the non-linearProcess-safe Operation classes.If later in develo
After JDK5, Java provides a more convenient security mechanism that uses lock locks for thread-locked operations and release operations without using synchronized . More clear. Example:Lock lock=new Reentrantlock ();Lock.lockCode that needs to be lockedLock.unlockWhy is lock more secure? Because synchronized may cause deadlock phenomenon, specifically about the deadlock phenomenon can refer to the operating system, there is no more to say.Summarize th
Java Exception Common interview question one, Java exception understandingExceptions are mainly handling errors that cannot be caught at compile time. The problem can continue to execute smoothly, without causing the program to terminate, to ensure the robustness of the program.Processing: When an abnormal state is generated, if the current context does not have
Java interview question Summary 2 (Continuous updates), java questions
1. How to format a date
Answer:Date now = new Date ();
SimpleDateFormat sdf = new SimpleDateFormat ("yyyy-MM-dd hh: mm: ss ");
String formatNow = sdf. format (now );
The formatNow variable is the formatted date.
2. What are several implementation m
in February.
The first day of 1751 in England was March 25, 11 days worse than France.After the United States adopted the Gregorian calendar, it went back hundreds of years, so that the dates originally recorded could be expressed in two calendars (usually to provide two dates for more precise purposes). For example, George Washington's birthday changed from February 1731 11 to February 1732 22.When you read a volatile variable in a thread, you can eventually read the value that it updated.A f
Java Questions Answers
1. What is the difference between an applet and an application?
A Java application is made up of a main () method declared as public static void that accepts a string array argument, along with any other classes that main () CILS. it lives in the environment that the Host OS provides.
A
create threads, how to create threads better (such as inheriting the thread class or calling the Runnable interface), and then gradually ask about concurrency problems like the Java memory model encountered in the process of Java concurrent programming, JDK1.5 introduces higher-order concurrency tools, common design patterns for concurrent programming, classic multithreading issues such as producer consume
wrapper type , which means that the wrapper type can be converted directly to the base data type , as shown in the following code:int m=100; Integer im=int N=im; The appeal code directly assigns m to the wrapper object IM, which is automatically boxed and then directly assigns the IM to the basic data type N, which is the automatic unpacking. Although the code on the surface is simple and convenient, however, in essence, the container still uses new to create the object, while unpacking is s
Java interview 30 Question 1: What are the differences between final, finally, and finalize.Second, can anonymous inner class (anonymous internal class) be extends (inherited) other classes, or implements (implemented) interface (Interface )?Third, the difference between static nested class and inner class is that the more you say, the better (the more general the inter
; k ) TestFunction (k, J, i);On the basis of scenario one, this scheme puts the instantiation of the cyclic variables out of the loop, which can further reduce the number of instances of the related cyclic variables, and the scheme time-consuming situation is as follows:
Variable
Instantiation (number of times)
Initialization (number of times)
Comparison (number of times)
Self-increment (number of times)
I
1
1
10
1
Java custom generic interview questions: receive any array to reverse, java custom
You can only operate on a certain type for reversal without using the generic type.
The Code is as follows:
package com.swift.fanxing;import org.junit.Test;public class RenyiReverse { @Test public void test() { int arr[]=new
take out 1 position: Product: 4 The consumer takes out from 0 position: Product: 2 producer put in 0 position: Product: 5 consumer removed from 0 Position: Product: 5 producer put in 0 position: Product: 6 consumer is removed from 0 position: Product: 6 producer put in 0 Location: Product: 7 producer puts 1 position: products £ º The producers are placed in the location of the product: 8 Position: Product Consumer removed from 1 position: Product: 9 consumer removed from 0 positions: Products:
threads are not able to modify objects in the collection that is being traversed by iterator. At the same time, iterator allows the caller to delete elements from the underlying collection, which is not possible for enumeration.What is the difference between 17.HashSet and TreeSet?HashSet is implemented by a hash table, so its elements are unordered. The time complexity of the add (), remove (), contains () method is O (1).On the other hand, TreeSet is implemented by a tree-shaped structure in
adapter pattern?
Ø database How are you usually optimized, what other tools are used to optimize no, how to use the
Ø Now there is a lot of tables to correlate the query SQL, the child table data is very much, then you only from the SQL point of view of the SQL statement optimization, do not need to consider the index, predicate
Ø you don't have a Java project, do you?
Ø your major is to control the direction, why do the current direction
O you have
, and future to implement threads with return resultsThe Executorservice, callable, and future three interfaces are actually executor frameworks. The thread that returns the result is a new feature introduced in the JDK1.5, and with this feature it is no longer necessary to get the return value. And it can be flawed if it is achieved.A task that can return a value must implement the callable interface. Similarly, a task without a return value must implement the Runnable interface.After performin
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