core java syllabus

Alas, the front has been skipped, a look at the pure text description on the headache.This section is about Java data types, there are eight basic types, of which the int,short,long,byte four are shaped, is pure numbers, the size is 4,2,8,1 bytes, a byte is composed of 8 01, the highest bit is the sign bit, 0 is an integer, 1 is a negative number, For example, the range of byte is 128 to 127. I don't know the rest of it.Floating-point types have float

complete most functions of the field****************An iterator is a design pattern that is an object that can traverse and select objects in a sequence, and the developer does not need to know the underlying structure of the sequence . Iterators are often referred to as "lightweight" objects because they are less expensive to create.The iterator functionality in Java is relatively simple and can only be moved one way:(1) Use Method iterator () "Call

Java operating mechanism the JVM of the core mechanism The JVM is the runtime environment for Java programs The JVM is part of the JRE, it is a fictitious computer, or it can be understood that the bytecode file is interpreted as a machine instruction on a specific platform when the byte code file is executed by the CPU JVM with the byte code as the machine in

Recently I read core Java, but I have never understood it before. I have read many posts and blogs and finally understood it. In Java, the char [], String, stringbuilder and stringbuffer class adopts UTF-16 encoding, using U + 0000 ~ U + FFFF represents a basic character (BMP character), but Char located in U + d800 to U + dbff and U + dc00 to U + dfff is conside

in any order, but are always retrieved in sorted order. Whenever the Remove method is called, the smallest element in the current priority queue is always fetched, but the priority queue is not sorted.Use data Structure = = "HeapThe heap is a self-adjusting two-fork tree. You can have the smallest elements move to the tree root without having to spend time sorting.Typical case: Task schedulingPriorityqueue ();Constructs a priority queue for holding compareable objectsPriorityqueue (int initialc

InstantiationException, IllegalAccessException { returnnew PairnewInstance(), c.newInstance());}CallmakePair(Employee.class);The type parameter T matches the Employee.Generic type information in a virtual machineYou can use the reflection API to determine: This generic method has a type parameter called T. This type parameter has a subclass qualification, which is itself a generic type. This qualified type has a wildcard parameter. This wildcard parameter has a superclas

Java -- JDK dynamic proxy core source code parsing, java -- jdk source code 1. First, let's take a look at how to use JDK dynamic Proxy: Public static void main (String [] args) {/*** creates a Bean object that implements the BeanInterFace interface */BeanInterFace bean = new Bean (); /*** create a MyProxy object that implements the InvocationHandler interface an

simple test, that is, do not use the exception to do the program to determine the branch; 2) to properly use the exception hierarchy, throw or capture, to try to use a class that can express a specific purpose, which will have better readability, Do not use throwable at all times, so that the readability is poor, 3) in the detection of errors, "harsh" than laissez-faire better, such as Stack.pop () is the return of NULL better or run out emptystackexception better? The author thinks the latter

IncreaseDeleteThe Remove method allows you to delete a specified element.Find*************************************************HashSet can neither use the index of 0 1 2 3 to determine the value of an element, nor use key to determine the value of an element*********************HashSet like this ["AA", "BB"] grow into such a data structure******************HashMap grow into such {a=123, B=hello}Jsonobject very much like {"A": 123, "B": null} *hashmap* *hashset*

Java has become a large and complex technology platform, for developers to better grasp the Java technology, in-depth understanding of the underlying technical processing details is essential. Mastering core concepts and ideas can help us extrapolate and comprehend by analogy and help us improve our understanding of the entire

The Java Collection class library separates the interfaces and implementations of the set. The same interface can be implemented differently. The basic interface of the Java Collection class is the collection interface. The collection interface must implement the iterator interface. To indicate the interfaces of the Collection framework, java. Lang and

Core Java Questions and Answers (1-33), answers1-33Preface Http://www.journaldev.com/2366/core-java-interview-questions-and-answers.What are the important features of Java 8? Java 8 was released in March 2014, which is very common

Today's early failure, coupled with a busy day overtime work, did not follow the plan to summarize Java-related technology, just see the following article summarizes the good, reproduced. What are the four core technologies of Java? First of all, we need to understand the importance of Java

Java core --- EnumerationI. Create a final-state Season class using enumeration in the form of common classes and set the constructor method to private, because the enumeration value cannot be added at will because the class object cannot be new, therefore, you need to define the member variables and write new in the class so that you can access the enumerated values outside the class by using the static me

Http://www.cnblogs.com/xzpp/archive/2011/10/10/2206619.html 1. Core dump and heap dump files Core DumpStores CPU and JVM-related information. It mainly stores the running position of each Java application thread at a certain time point, that is, the method of the class to which the execution is performed and the line. Javacore is a text file. Once opened, the exe

j2ee| detailed Java was originally staged in browsers and client machines. At the time, many people questioned whether it was suitable for server-side development. Now, with the increase in Third-party support for the JAVA2 platform Enterprise version, Java is widely accepted as one of the preferred platforms for developing enterprise server-side solutions. The Java