The previous section had a rough understanding of the operator. This section reviews program flow control! Program flow control includes sequence structure, judgment structure (if), selection structure (switch), and loop structure.
1. Judgment structure ①The first format of if statement:
if (conditional expression)
{
into the ternary operator.
Execution statement;
; }
2.选择结构
switch(表达式)
{
case 取值1:
执行语句;
case 取值2:
执行语句; break;
…...
default:
When making a selection, switch first selects the first valid choice, and if neither is true, then selects default; the switch execution structure ends when it encounters curly brackets or break, otherwise it continues to execute until the condition is true!
Special case:
int x = 2; //break;
out.println ("a"); :
System.out.println("c");
break;
’’’ With d a b’s output d a b, principle: there is no break when executing to default, and default is placed at the front, so it will continue to execute downwards without judging other answers, and the executable statements will be executed according to the sequential structure. Until break or the end of the curly bracket is encountered, so the output order should be d a b;
application of if and switch:
if:
1. Judge the specific value.
2. Judge the interval.
3. Judge the expression whose operation result is boolean type.
switch:
1. Judge the specific value.
For several fixed value judgments, it is recommended to use the switch statement, because the switch statement will load the specific answers into the memory.
The efficiency is relatively high. 3. Loop structure ①.while method:
while (conditional expression)
Conditional expression);
③.for method:
for (initialization expression; loop condition expression; operation expression after loop)
In the running sequence, the initialization expression is read only once, the loop body is executed when the loop condition is true, and then the operation expression after the loop is executed, and then the loop condition is continued to be judged, and this process is repeated until the condition is not satisfied.
defined for the loop's variable is released in the memory at the end of the for loop, while the variables used in the while loop can continue to be used after the end of the loop.
The simplest infinite loop format: while (true), for (;;), the reason why infinite loop exists is that we don’t know how many times it will loop, but judge the loop based on certain conditions.
4. Other flow control statements
break (jump out) statement: Scope of application: selection structure and loop structure.
句 B, there are no sentences below these two statements, because it cannot be executed. U C, Continue statement is to end this cycle and continue the next cycle. , D, the appearance of the label can make these two statements affect the specified range.
Example: Example of labeling: xiaoqiang:for (int x=0; x{ System. out.println (" Net (www.php.cn)!
Bytecodeachievesplatformindependencebybeingexecutedbyavirtualmachine(VM),allowingcodetorunonanyplatformwiththeappropriateVM.Forexample,JavabytecodecanrunonanydevicewithaJVM,enabling"writeonce,runanywhere"functionality.Whilebytecodeoffersenh

Java cannot achieve 100% platform independence, but its platform independence is implemented through JVM and bytecode to ensure that the code runs on different platforms. Specific implementations include: 1. Compilation into bytecode; 2. Interpretation and execution of JVM; 3. Consistency of the standard library. However, JVM implementation differences, operating system and hardware differences, and compatibility of third-party libraries may affect its platform independence.

Java realizes platform independence through "write once, run everywhere" and improves code maintainability: 1. High code reuse and reduces duplicate development; 2. Low maintenance cost, only one modification is required; 3. High team collaboration efficiency is high, convenient for knowledge sharing.

The main challenges facing creating a JVM on a new platform include hardware compatibility, operating system compatibility, and performance optimization. 1. Hardware compatibility: It is necessary to ensure that the JVM can correctly use the processor instruction set of the new platform, such as RISC-V. 2. Operating system compatibility: The JVM needs to correctly call the system API of the new platform, such as Linux. 3. Performance optimization: Performance testing and tuning are required, and the garbage collection strategy is adjusted to adapt to the memory characteristics of the new platform.

JavaFXeffectivelyaddressesplatforminconsistenciesinGUIdevelopmentbyusingaplatform-agnosticscenegraphandCSSstyling.1)Itabstractsplatformspecificsthroughascenegraph,ensuringconsistentrenderingacrossWindows,macOS,andLinux.2)CSSstylingallowsforfine-tunin

JVM works by converting Java code into machine code and managing resources. 1) Class loading: Load the .class file into memory. 2) Runtime data area: manage memory area. 3) Execution engine: interpret or compile execution bytecode. 4) Local method interface: interact with the operating system through JNI.

JVM enables Java to run across platforms. 1) JVM loads, validates and executes bytecode. 2) JVM's work includes class loading, bytecode verification, interpretation execution and memory management. 3) JVM supports advanced features such as dynamic class loading and reflection.

Java applications can run on different operating systems through the following steps: 1) Use File or Paths class to process file paths; 2) Set and obtain environment variables through System.getenv(); 3) Use Maven or Gradle to manage dependencies and test. Java's cross-platform capabilities rely on the JVM's abstraction layer, but still require manual handling of certain operating system-specific features.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

SublimeText3 English version
Recommended: Win version, supports code prompts!

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function
