core java certification

Mastering Java Core Technology is the key to learning and mastering Java technology, with 17 points below to explain these Java core technologies. No more inheritance in 1.Java, but instead of multiple inheritance with interfaces

: Network Disk DownloadContent Introduction Editor Cays.horstmann, Gang Fei compiled "Java Core technology" (Corejava) since the 1th edition of the publication, has been the majority of Java program designers favor, best-selling, is the Java classic books. The 8th edition has been comprehensively updated for the JavaSE

development tools, such as Java, Javac (Java compiler)DB directory: Java-developed database Apache Derby, is an open source 100%java developed relational database, with not much.Include directory: the C language header file supports native code programming with the Java loc

Transferred from: https://www.oschina.net/question/3756233_2277445Multi-line threads for other Java knowledge points, there is a certain threshold for learning, and it is more difficult to understand. In peacetime work if improper use will appear data confusion, inefficient execution (as a single-threaded to run) or deadlock program hangs and so on, so mastering the understanding of multithreading is critical.From the beginning of the basic concept to

-code unit S u+d835 and u+dd6b. (see http://en.wikipedia.org/wiki/UTF-16 for a description of the encoding algorithm.) in Java, the char type describes a code unit in the UTF-16 encoding.Our strong recommendation isn't to use the char type in your programs unless you are actually manipulating UTF-16 cod E units. You is almost always better off treating strings as abstract data types.3.3.4. The Boolean Type The Boolean type has two values, false and Tr

the implementation of the interface class to realize the replacement system.Definition of the interface:1. The naming conventions and classes of the interfaces are the same.Example: public interface interface Name {}2. Constants can be defined in the interface, and variables cannot be defined. The properties in the interface are automatically modified with public static final. The constants in the interface must specify the initial values when they are defined.3. The methods involved in the int

thread is an object in Java, what are the properties of this object? Thread properties can be divided into static and dynamic properties, static here refers to the programmer is immutable, there is a JVM allocation, dynamic refers to the programmer can be customized, although the JVM gave the default property values. Static attributes: ID, etc., Dynamic properties: Name,priority,deamon,group,classloader, etc. So much for the basics, that's what it's

) Data type conversions A solid arrow in the diagram indicates a loss-free conversion, and a dashed arrow indicates a conversion that may have a loss of precision. (e.g. 123 456 789 (int) is a large integer that contains more bits than can be expressed by the float type (a valid number 6~7 bit), and when this integer value is converted to float, the result is the same size, But the loss of a certain degree of accuracy (after the number of decimals can not be ac

and implementation of interface Autowirecapablebeanfactory Configurablelistablebeanfactory:beanfactory configuration checklist, specifying the green type and interface Defaultlistablebeanfactory: Combines all of the above functional groups to be processed after the bean is registered 2.XmlBeanDefinitionReader From this diagram we can see how this class is packaged in a step-by-step way.

Tags: Get select instance expression oca important localhost share databaseThe Java Tag Library is divided into the above several, generally used is the core and functions, the next will explain the various, and common usage. The General tag library is used with the El expression, so the use of the El expression is also studied before learning the tag library. Expand after import The corresponding tag libr

Java core technology: an in-depth understanding of abstract classes and interfaces1. General description Abstract classTemplate Method ModeInterface2 abstract class Abstract classes are classes that cannot be instantiated. They are generally designed to inherit from quilt classes to implement abstract methods of parent classes.The biggest difference from a common class is that it cannot be instantiated. You

This article is based on the 12th chapter of the Java Core Reel, and the more detailed information is in the Java core Reel.1. Generic types can only be reference types and cannot use basic data types. 2. Type variable meaning　　 E: set K: keyword V: value T: any type 3. Generic class　　3.1 PrecautionsType variable d

Java cache Ehcache-core class and method introduction and use instance, javaehcache-Core classes and methods in Ehcache The EhCache contains a CacheManager type, which is used to manage the cache. The Cache stores the Element object. The Element must be a key-value pair. The Cache is physically implemented in the memory or disk. The logical representation of the

1. PrefaceRecently, I've seen several interesting questions about the Java Core class string. The string class is how to implement its immutable attributes, and the benefits of being designed to be immutable. Why is it not recommended to use the + sign to form a new string, it is recommended to use StringBuilder or StringBuffer. Flip through some of the online blogs and StackOverflow, comb

No more inheritance in 1.Java, instead of multiple inheritance with interfaces2. When running a compiled program, the Java interpreter always executes from the code in the main method of the specified class, so there must be a main function in the execution code.3.Java is a typical strongly typed language, that is, you must declare the type of the variable, there

slower than just calling the method directly, so it is advisable to use the method object only when necessary, preferably with an interface and a lambda expression.In particular, we recommend that Java developers not use the callback function of the method object. Using an interface for callbacks can make your code execute faster and easier to maintain.7.8 Inherited design Tips1. Placing public operations and domains in a super class2. Do not use pro

[] getdeclaredannotations ()//returns TRUE if the program element is a specified type annotation adornment, otherwise returns Falseboolean Isannotationpresent (classThe example code that parses our custom annotation MethodInfo above is as follows (Annotationparser.java):public static void Main (string[] args) { try { Class cls = annotationtest.class; For (Method method:cls.getMethods ()) { MethodInfo MethodInfo = method.getannotation (methodinfo.class); if (me

Multicore CPUs are now the mainstream. Using multi-core technology, can effectively play the ability of hardware, improve throughput, for Java programs, can implement concurrent garbage collection. However, the use of multi-core technology in Java also brings some problems, mainly because of multi-threaded shared memor

Over the last one months. Just swallowed the book over. The book is long enough to say 706 pages. I have never been a person who likes to record, have been reading what books have been read to throw aside, may sometimes have so a little want to record down the impulse, but the calculation time is too tight, a lot of youshiwuzhong, after all, research and research program is only a hobby of their own, but did not expect to sign a programmer's work. Alas, this God is too much fun, let a study of e

JAVA concurrencyParallel programming in Java is complicated, and I don't understand it deeply. But recently, due to the parallel training of classifiers, pondering a little, there are errors please correct me. Just a rough introduction.Many problems we use sequential programming can be solved, but some problems if you can use multi-threaded parallel execution of the task of which can greatly improve the tim