java interview questions and answers pdf

into the corresponding method to invoke the logical layer of the method to achieve response to the customer.There are no doget, dopost, and so on in the Servlet interface and Genericservlet, these methods are defined in HttpServlet, but all return error information, so, each time we define a servlet, Must implement these methods such as Doget or Dopost.Each custom servlet must implement the Servlet interface, and the Servlet interface defines five methods, of which the more important three meth

Sword refers to Java Implementation of offer programming questions-the integer power of the value of interview question 11, and sword refers to offer Question: Implement the double power (double base, int exponent) function to calculate the power of base's exponent. Do not use library functions, and do not need to consider large numbers. Solution: the most common

Sword refers to the Java Implementation of offer programming questions -- interview question 6 re-constructs a binary tree, and sword refers to offer Question: Enter the result of the forward and middle traversal of a binary tree. Create a New Binary Tree. Assume that the input results do not contain repeated numbers.For example, if the input preorder traversal s

Sword refers to Java Implementation of offer programming questions -- interview question 13 deletes linked list nodes in O (1) time, and sword refers to offer Question: given a one-way linked list head pointer and a node pointer, define a function to delete the node at O (1) time. Given a one-way linked list, the time complexity of normal Chain List deletion is t

Java --------------- String basic interview questions Package stu. love. a;/* String: */public class StringDemo {public static void main (String [] args) {// the String is a constant. Once a String is created, the String ss = "hello"; ss = "world"; System. out. println (ss); // special case:/* when defining s2, go to the constant pool to check whether the string

configuration. While JavaScript is interpreted to perform without generating intermediate files, "read a sentence, execute a sentence", the execution can generally be done in three ways:1. The general browser comes with the JS interpreter, which can be used directly by the browser;2. Special interpreter software can be installed node. js, executing the. js file;3. Executed with the Web page, using the Third, the data typeJava is a strongly typed language, and when it comes to data, the declarat

Analysis:Store basic data types1. Create an arr reference in the stack2. Create an int array of length 3 in the heap and initialize it, assigning the default value of 03. Point an ARR reference to an int array4. Re-assign values to each int value in an int arrayStore reference type User1. Create a Userarr reference in the stack2. Create a user array of length 3 in the heap and initialize it, assigning a default value of NULL3. Point the Userarr reference to the user array4. Create a user1,user2

Java multi-thread interview questions 1. What is the difference between ArrayList and Vecoter? Similarities and differences between Array and ArrayListI. Differences between Array and ArrayList#1. variables of the Array type must be instantiated at the same time (at least the size of the Array must be initialized), while ArrayList can only be declared first.For e

(throughput) collector?The throughput collector uses a parallel version of the new generation garbage collector, which is used for medium-sized and large-scale data applications. The serial collector is sufficient for most small applications, which require about 100M of memory on modern processors.7. In Java, when can objects be garbage collected?This object can be recycled when the object becomes inaccessible to applications that currently use the o

. At the same time if there are multiple threads accessing Hashmap,collections.synchronizedmap () can be substituted, generally hashmap more flexible.10. Why is the vector considered to be obsolete or unofficially deprecated? Or why we should always use ArrayList instead of vectors.You should use ArrayList instead of vectors because by default you are non-synchronous, vectors synchronize each method, you almost never do that, and usually you want to synchronize the entire sequence of operations.

Java programmer interview questions (86-115) 86. In Struts 2, how does Action obtain the data that the user inputs from the page, and how does it transmit its own data to the view? A: There are three ways for Action to retrieve data from the page: 1) accept parameters through the Action attribute 2) obtain parameters through the domain model 3) ModelDriven )

Java multithreading interview questions Induction1. What are the implementation methods for multithreading? The following example shows the thread synchronization. (1) Java multithreading has two implementation methods: Inheriting the Thread class and implementing the Runnable interface. Thread implements the Runnable

values that cannot be changed. The string provided by this StringBuffer class is modified. You can use StringBuffer when you know that character data is going to change. Typically, you can use Stringbuffers to dynamically construct character data.5. What are the similarities and differences between abnormal operation and general anomaly?An exception represents an unhealthy state that may occur during a program's run, and a run-time exception that represents an exception that may be encountered

are characterized by the inability to define variables, and all methods are abstract methods . abstract classes can have variables and do not enforce the need for abstract methods .Inheritance of class 16 and implementation of interfacesParsing: Class Inheriting the parent class implements the interface with the class, which is essentially the same. is to either extend or rewrite the parent class or interface as a template on this template. In practical programming, programmers often need to in

, 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

Sword refers to Java Implementation of offer programming questions -- interview question 4 replaces spaces, and sword refers to offerImplement a function to replace spaces in a string with "% 20 ". For example, if the string is We Are Happy, the replaced string is We % 20Are % 20 Happy. 1 package Solution; 2 3/** 4 * offoffoffer

Analysis and Summary of Baidu Java R D interview questions 1. Analysis of Common application scenarios in singleton mode. Among the 23 design modes, the singleton mode is the largest. It is easy to understand, but applicable to scenarios. Are you really familiar with this? The use of Singleton is because there is no need to create an object for each request, wh

One: The difference between Eclipse and MyEclipseA: 1 common: Both are used to develop Java projects, and software usage is almost identical2 MyEclipse is a fee-free software, which can develop both Java and Web projects, Eclipse can only develop Java projects, if you want to develop a Web project, but also need to add additional Eclipse Web plug-in (of course, c

default branch, which must be the last branch of a switch statement. (3) default is executed when no case statement is equal to the value of the variable. The default branch does not require a break statement.Break is used to interrupt the loop statement, and continue is used to continue the loop. Breake break out of the loop body, continue continue the next loop, but the statement after continue is not running. Continue can only be used in loop statements, and break may be used in other branch

As a Java programmer who is often asked in an interview, let me summarize some of the questions that I often don't ask. The difference between 1.HashMap and Hashtable Often asked. Both are classes of the map interface, which enable you to map a unique key to a specific value. HashMap class is not sorted and can have a null key and multiple nul