Programmer Group

Difference 1. String is a constant, StringBuilder, StringBuffer is a variable. 2. The methods and functions in StringBuffer and StringBuilder are completely equivalent. 3. Only the methods in StringBuffer mostly adopt synchronized keywords to modify, so they are thread-safe. StringBuilder, without this modification, can be consi ...

1. Enumeration (actually multiple cases) Enumerations in java are defined using enum, which is not a new structure. Enumerations are defined using enum The Enum enumeration class is actually inherited by default.So the enum structure defined by enum is actually a multiple-instance class. Three commonly used methods for 1.1Enum e ...

In a previous discussion with a bull, I found that my knowledge of AOP was not thorough enough, so in the recent period of study, I combed the AOP related knowledge again. What is AOP AOP refers to facet-oriented programming, which mainly extracts some common functions required by business logic from the business implementatio ...

Article directory Classification of GoF Design Patterns 1.1 Creative 1.2 Structural Type 1.3 Behavioral Type II. Overview of Design Principles 2.1 Summary of Object-Oriented Design Principles: 2.2 Single Responsibility Principle 2.3 Open-Close Principle 2.4 Richter Substitution Principle 2.5 Dependence on reversal principl ...

I. String class 1. Classification of strings: Immutable String: When an object is created, its content cannot be changed. Once the content changes, it is a new object. Variable String Builder/String Buffer: When the object is created, the content of the object can be changed, and when the content changes, the object remains unch ...

Preface Today, I encountered a bug. The phenomenon is that a task is put into the thread pool, which seems to be "not executed" and the log is not typed. After debugging the local code, it was found that NPE was thrown in the first half of the task logic, but there was no try-catch in the outer part of the code, which led to the excep ...

(1) Comparisons when performing put (K key,V value) operations: The source code in JDK 1.7 is as follows public V put(K key, V value) { if (table == EMPTY_TABLE) { inflateTable(threshold); } if (key == null) //If the key is null, the put for NullKey (Value) operation is performe ...

Preface float and double are designed for scientific calculation and engineering calculation. They provide fast and accurate calculations over a wide range of numerical values. However, they do not provide completely accurate results, so they can not be used in situations requiring accurate results. But commercial calculations requ ...

Inheritance can extend the function of the parent class by reusing the parent code, but at the same time it increases the coupling between objects, so inheritance should be used cautiously. So is there a way to extend the functions of parent classes and decouple objects? The answer is yes. That's the decorator model we're going to learn today. ...

BS53 project uses java reflection to get custom controls, then instantiates them and displays them on the page. It realizes that only one configuration file is needed to display the whole page, and supports different configurations in 5 styles. Basically all depends on reflection technology. Now let's take a brief look at reflection technology ...