best book for java interview preparation

Thank you for attending our interview:　　The following is a summary of some pre-interview preparation and technical reference questions, hoping to help you.First, you need to prepare a job-related self-introduction, including the following:1. Several years of Java development experience, probably summarized under what t

Today we will be divided into four parts to talk about this problem, because I am a Java origin, so about the main language problems are related to Java, other language students can selectively ignore. In addition, the interview when the general interviewer's problems are closely linked, gradually in-depth, this point in the following can be more clearly felt.1,

= mysql_query("SELECT * FROM user WHERE country = ‘China‘"); if0) { ... } // 有效率的： $r = mysql_query("SELECT 1 FROM user WHERE country = ‘China‘ LIMIT 1"); if0) { ... } 4. Jianjian Index for search wordsRefer to Java interview Preparation 15: Database--Index 5. Use a fairly typed example in the Join table and index itIf your application has many join que

generation object will replicate multiple times in the Survivor area, which can increase the lifetime of the object's younger generations, increasing the probability that it will be recycled in the younger generation. The parameter is valid only for serial GC.-xx:pretenuresizethreshold object more than how large is directly in the old generation to allocate 0 units of bytes The Cenozoic adopt parallel scavenge GC When invalid another case is a large array object that is allocated directly in th

through the HashMap bottom to achieve, but is HashMap value is all assigned to a constant object object, internal additions and deletions and other methods are directly called HashMap method, so do not repeat, and so on, such as HashMap in-depth analysis. private transient hashmap map; private static final object PRESENT = new object ( ); public boolean add (e e) { return map.put (E, PRESENT) ==null ; public boolean remove (Object o) { return map.remove (o) ==present;

a behavior, once the behavior changes, there is no need to modify many classes, just modify this behavior. AOP is this decentralized programming approach that encapsulates "focus" in "facets"2) control reversal IOC (inversion of control) controls refers to dependencies between program-related classes. In traditional conceptual design, it is usually the caller who creates an instance of the callee, in Spring, the work of creating the callee is no longer done by the caller, but by the The Spring

In Java, exceptions are classified as checked exceptions, and run-time exceptions. Both are in the exception class hierarchy. This type of easy-to-choose quiz did you master the exception class and know which exception classes must be capturedThe following figure shows the inheritance relationship of the Java exception class.Figure 1The pink is the checked exception (checked exceptions), which must be captu

framework, you'll think of Collectoin, and you'll answer arraylist\hashmap\hashset, and you'll talk about their differences. If more in-depth, hashmap principle, For-each principle and copyonwritearraylist, arrayblockingqueue and chat to these two classes, And then we'll talk about the problem under the java.util.concurrent bag.1.Collectoin Set Frame2.arraylist\hashmap\hashset differences3.HashMap principleRefer to the following two links, as long as you understand should be no problem, simply

.-abstract class can have attribute, interface can only have method. -the method of an interface must not be implemented, and an abstract class can have an implementation method.-the method in the interface is default and must be public , and the abstract class can be protected. 3. Instantiate a process for a class that has not been loaded.See the book.4. Error errors and exception exception classification, throws and throw differences.Java exceptions

+ + relies on some non-standard libraries provided by other vendors.Common written Questions:The following statements are wrong ()A:java Object-oriented language allows individual processes and functions to existB:java Object-oriented language allows separate methods to existMethods in the C:java language belong to members in the Class (member)A method in a D:java language must be subordinate to a class (object), and the calling method is the same as a procedure or functionAnswer: A, B, C. See

use R2 in addition to R1, ... So go on until you can divide it evenly. The last non-0 divisor is (A, b).Time complexity O (logn).String s = "a" + "B" + "C" + "D" + "E"; how many objects are created?1 of them. "A" is a constant and only the literal value is stored.What are the output results of the following programs?String str = "ABCDEFGH";System.out.println (str.dubstring (3,5));Answer: "DE"What's the difference between StringBuffer and StringBuilder?The newly introduced StringBuilder class is

Summary of JAVA programmer interview book-let's talk about my understanding September 7, 2014 I started reading this book today and ended the systematic training at the intermediate level of the algorithm in the original plan. I think let's take a look at the interview quest

assignment statement s= "" is a reference to a string type that points to another string (the value of the string is "", or an empty string).Common written Questions:New String ("ABC") has created several objects?Answer: one or two. Assuming that there is an "ABC" in the constant pool, then just create an object, assuming that there is no string "abc" in the constant pool, then two objects will be created.Fromp=180 ">java Program Ape

type modifier (typespecifier). It is designed to modify variables that are visited and changed by different threads. Variables defined by the volatile type are extracted directly from the corresponding memory each time the system uses it, rather than using the cache. After using the volatile modifier member variable, the values of the variables that all threads see at any time are the same. A demo sample using volatile is given below. public class mythread Impl ements Runnable

Reading today finds a very interesting question.What will the following program output?public class Test2 {public static void Main (string[] args) {int j = 0;for (int i = 0; I J = j + +;}System.out.println (j);}}The result of the output is: 0 just saw the time to feel very strange, I chose the answer is 100, and then read the book to explain what is the middle cache variable, the result of the mess, the final discovery actually explained is very simp

is random.What's the difference between HashMap and Hashtable?Hastmap is an interface that is a sub-interface of the map interface, an object that maps keys to values, where the keys and values are objects and cannot contain duplicate keys, but can contain duplicate values. HashMap allows null key and null value, while Hashtable is not allowed.HashMap is a lightweight implementation of Hashtable (non-thread-safe implementation).Constructors are not overridden in

be a deliberate consideration for Java designers. As a program designer, when an expression of J=f (j) is present, it must be the final value of the entire expression of F (j), rather than the value of J being increased by various self-decrement in the process (if so, that f (*) is meaningless, rather than simply preserving the various self-increment of J and throwing away other subtraction expressions), So the value of F (j) cannot be covered by the