PHPJava - JVM Emulator by PHP

What is PHPJava?

PHPJava is an experimental library which emulates JVM (a.k.a. Java Virtual Machine) by PHP 🐘 And PHPJava reads binary from pre-compiled Java file(s) ☕ So, PHPJava is NOT bridge to Java. This library can be run 100% in PHP. This project referred to Java Virtual Machine Specification documentation at the time we made it.

We are welcoming any contributions to this project 💪

Contribution guide is here:

• The Contribution Guide

Documents

• English
• 日本語

DEMO

Requirements

• PHP >= 7.2
• Composer
• ext-zip

Run with PHPJava's binary

You can run PHPJava as same as an executable binary.

Run Class

./vendor/bin/PHPJava HelloWorld

or

./vendor/bin/PHPJava HelloWorld.class

Run Jar

./vendor/bin/PHPJava -m jar HelloWorld.jar

help

./vendor/bin/PHPJava -h

Quick start

1. Install PHPJava in your project:

$ composer require php-java/php-java

2. Write Java:

class HelloWorld 
{
    public static void main(String[] args)
    {
        System.out.println(args[0]);
    }
}

3. Compile Java:

$ javac -encoding UTF8 /path/to/HelloWorld.java

4. Call the main method as follows:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;
 
JavaClass::load('HelloWorld')
    ->getInvoker()
    ->getStatic()
    ->getMethods()
    ->call(
        'main',
        ["Hello World!"]
    );

// Or, you can specify file path as follows. 
(new JavaClass(new JavaCompiledClass(new FileReader('/path/to/HelloWorld.class'))))
    ->getInvoker()
    ->getStatic()
    ->getMethods()
    ->call(
        'main',
        ["Hello World!"]
    );

5. Get the result

$ php /path/to/HelloWorld.php
Hello World!

Java Archive (Execute *.jar file)

1. Build your Java files into a class:

$ javac -encoding UTF8 -d build src/*
$ cd build && jar -cvfe ../Test.jar Test *

2. Execute the jar on PHPJava with either an enrtypoint or your target method.

<?php
use PHPJava\Core\JavaArchive;

// You must pass parameters to entrypoint within the `execute` method.
// The `execute` method does not have any default parameters.
(new JavaArchive('Test.jar'))->execute([]);

// or
(new JavaArchive('Test.jar'))
    ->getClassByName('Test')
    ->getInvoker()
    ->getStatic()
    ->getMethods()
    ->call(
        'main',
        []
    );

Get/Set static fields

e.g., Set or Get static fields:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$staticFieldAccessor = JavaClass::load('HelloWorld')
    ->getInvoker()
    ->getStatic()
    ->getFields();

// Set
$staticFieldAccessor->set('fieldName', 'value');

// Get
echo $staticFieldAccessor->get('fieldName');

Call a static method

e.g., Call a static method:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

JavaClass::load('HelloWorld')
    ->getInvoker()
    ->getStatic()
    ->getMethods()
    ->call(
        'methodName',
        $firstArgument,
        $secondArgument,
        $thirdArgument,
        ...
    );

// Or, if the called method has a return value, you can store it to a variable.
$result = JavaClass::load('HelloWorld')
   ->getInvoker()
   ->getStatic()
   ->getMethods()
   ->call(
       'methodWithSomethingReturn',
       $firstArgument,
       $secondArgument,
       $thirdArgument,
       ...
   );

// Output the $result you want
echo $result;

Get/Set dynamic fields

If you want to get/set dynamic fields, you need to call the construct method on Java by PHPJava.

e.g., Call dynamic field:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$javaClass = JavaClass::load('HelloWorld');

$javaClass->getInvoker()->construct();

$dynamicFieldAccessor = $javaClass
    ->getInvoker()
    ->getDynamic()
    ->getFields();

// Set
$dynamicFieldAccessor->set('fieldName', 'value');

// Get
echo $dynamicFieldAccessor->get('fieldName');

Call a dynamic method

If you want to call a dynamic method (same as a field), you need to call the construct method on Java by PHPJava.

e.g., Call dynamic method:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$dynamicMethodAccessor = JavaClass::load('HelloWorld')
     ->getInvoker()
     ->construct()
     ->getDynamic()
     ->getMethods(); 

$dynamicMethodAccessor
    ->call(
        'methodName',
        $firstArgument,
        $secondArgument,
        $thirdArgument,
        ...
    );

// Or, if the called method has a return value, you can store it to a variable.
$dynamicMethodAccessor
   ->call(
       'methodWithSomethingReturn',
       $firstArgument,
       $secondArgument,
       $thirdArgument,
       ...
   );

// Output the $result you want
echo $result;

Call a method in a built-in package on Java

PHPJava can call a built-in package in the same way as JavaClass::load after the version 0.0.8.5. This feature is emulated by ReflectionClass on PHP and any static methods/fields will dynamically be generated in fact.

e.g.) To Call java.lang.Math is below.

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

echo JavaClass::load('java.lang.Math')
     ->getInvoker()
     ->getStatic()
     ->getMethods()
     ->call(
         'pow',
         2,
         4
     ); 

The example will return 16.

Call ambiguous methods in Java from PHP

• In PHP, types are more ambiguous than Java.
• For example, you may want to call a method that accepts a long parameter in Java from PHP. In this case, you can call that method as follows:

e.g., [Recommended] Wrap with \PHPJava\Kernel\Types\_Long.

In Java

class Test
{
    public static void includingLongTypeParameter(long n)
    {
        System.out.println(n);
    }
}

In PHP

<?php
$javaClass->getInvoker()->getStatic()->getMethods()->call(
    'includingLongTypeParameter',
    new \PHPJava\Kernel\Types\_Long(1234)
);

The example will return 1234.

e.g., Set false to strict mode option.

In PHP

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$javaClass = JavaClass::load(
    'HelloWorld',
    [
        'strict' => false,
    ]
);

Runtime options

• Available options on JavaClass or JavaArchive:

Options	Value	Default	Description	Targeted
entrypoint	string or null	null	The entrypoint in JAR.	JavaArchive
max_stack_exceeded	integer	9999	Execute more than the specified number of times be stopped the operation.	JavaClass
max_execution_time	integer	30	Maximum execution time.	JavaClass
strict	boolean	true	When true, PHPJava calls a method, variables, and so on strictly; otherwise, it calls them ambiguously.	Both
validation.method.arguments_count_only	boolean	false	When true, ClassResolver validates arguments by their number only.	JavaClass
operations.enable_trace	boolean	false	When true, PHPJava stores the operation history.	JavaClass
operations.temporary_code_stream	string	php://memory	Operation code will be output to temporary stream. Change this if your code is heavy so you'll be happy.	JavaClass
operations.injector.before	callable	null	Inject an executor before executing an operation.	JavaClass
operations.injector.after	callable	null	Inject an executor after executing an operation.	JavaClass
log.level	int	Logger::EMERGENCY	The output level of Monolog.	Both
log.path	string or resource	php://stdout	The output destination of Monolog.	Both
dry_run (Not Implemented)	boolean	false	Checking JavaClass/JavaArchive structure only. When true, PHPJava runs in dry-run mode.	Both
env (Not Implemented)	enum	Environment::EXPERIMENTAL	Your environment.	Both

• Example of JavaClass:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$javaClass = JavaClass::load(
    'HelloWorld',
    [
        'max_stack_exceeded' => 12345,
        'validation' => [
            'method' => [
                'arguments_count_only' => true,
            ],
        ],
    ]
);

• Example of GlobalOptions

<?php
use PHPJava\Core\JVM\Parameters\GlobalOptions;
use Monolog\Logger;

GlobalOptions::set([
    'log' => [
        'level' => Logger::DEBUG,
    ],
    'validation' => [
        'method' => [
            'arguments_count_only' => true,
        ],
    ],
]);

Output PHPJava operations

• Output debug trace if you want to see operation log:

<?php
use PHPJava\Core\JavaClass;
use PHPJava\Core\Stream\Reader\FileReader;

$javaClass = JavaClass::load('HelloWorld');

$javaClass
    ->getInvoker()
    ->getStatic()
    ->getMethods()
    ->call(
        'main',
        ["Hello", 'World']
    );

// Show debug traces.
$javaClass->debug();

• Output debug trace:

[method]
public static void main(java.lang.String[])

[code]
<0xb2> <0x00> <0x02> <0x2a> <0x03> <0x32> <0xb6> <0x00> <0x03> <0xb2> <0x00> <0x02> <0x2a> <0x04> <0x32> <0xb6> <0x00> <0x03> <0xb2> <0x00>
<0x02> <0x2a> <0x05> <0x32> <0xb6> <0x00> <0x03> <0xb1>

[executed]
      PC | OPCODE | MNEMONIC             | OPERANDS   | LOCAL STORAGE  
---------+--------+----------------------+------------+-----------------
       0 | 0xB2   | getstatic            | 0          | 1              
       3 | 0x2A   | aload_0              | 1          | 1              
       4 | 0x03   | iconst_0             | 2          | 1              
       5 | 0x32   | aaload               | 3          | 1              
       6 | 0xB6   | invokevirtual        | 2          | 1              
       9 | 0xB2   | getstatic            | 0          | 1              
      12 | 0x2A   | aload_0              | 1          | 1              
      13 | 0x04   | iconst_1             | 2          | 1              
      14 | 0x32   | aaload               | 3          | 1              
      15 | 0xB6   | invokevirtual        | 2          | 1              
      18 | 0xB2   | getstatic            | 0          | 1              
      21 | 0x2A   | aload_0              | 1          | 1              
      22 | 0x05   | iconst_2             | 2          | 1              
      23 | 0x32   | aaload               | 3          | 1              
      24 | 0xB6   | invokevirtual        | 2          | 1              
      27 | 0xB1   | return               | 0          | 1              
---------+--------+----------------------+------------+-----------------

• [method] shows the called method.
• [code] shows the JVM's real programs.
• [executed] shows the executed programs.
  • PC shows the Program Counter.
  • OPCODE shows the Operation Codes.
  • MNEMONIC shows the names of the Operation Codes.
  • OPERANDS shows the stacked items on memory.
  • LOCAL STORAGE shows the stacked items on a method.

About big number calculation

• In normally, PHP cannot calculate big numbers as such as long and double types. But, PHPJava uses external Math library for covering above problems. And, PHPJava to use Java's type as below comparison table. Therefore, we recommend to cast them to string on PHPJava. And, if it can be calculated with 64-bitPHP, PHPJava uses PHP's arithmetic operations.

Types of Java

• The comparison table of Java and PHPJava is shown below:

Java	PHPJava
null	null
boolean	\PHPJava\Kernel\Types\_Boolean (including __toString)
char	\PHPJava\Kernel\Types\_Char (including __toString)
byte	\PHPJava\Kernel\Types\_Byte (including __toString)
short	\PHPJava\Kernel\Types\_Short (including __toString)
int	\PHPJava\Kernel\Types\_Int (including __toString)
long	\PHPJava\Kernel\Types\_Long (including __toString)
float	\PHPJava\Kernel\Types\_Float (including __toString)
double	\PHPJava\Kernel\Types\_Double (including __toString)

Run Kotlin on the PHPJava

Do you wanna run Kotlin on the PHPJava? Are you serious? Haha, yes, you can, but this feature is currently experimental.

Quick Start

1. Write Kotlin:

fun main(args: Array<String>) {
    println("Hello World!")
}

2. Compile Kotlin:

$ kotlinc HelloWorld.kt -include-runtime -d HelloWorld.jar

3. Execute JAR:

<?php
use PHPJava\Core\JavaArchive;

$jar = new JavaArchive(__DIR__ . '/HelloWorld.jar');
$jar->execute([]);

You'll get the result: Hello World!.

Run unit tests

• To run a PHPUnit test:

$ ./vendor/bin/phpunit tests

• To run PHP Coding standards test:

$ ./vendor/bin/phpcs --standard=phpcs.xml src

• To run all tests:

$ composer run tests

Reference

• Java Virtual Machine Specification

License

MIT