Java

Java is a high-level, general-purpose, memory-safe, object-oriented programming language.

In LiveCodes, Java source is compiled to WebAssembly in the browser: a build of OpenJDK's javac and the TeaVM AOT compiler run as a single WebAssembly module inside a Web Worker. Nothing is sent to a server, and modern Java (records, var, text blocks, switch expressions) is supported.

The language is named java-wasm; java is an alias for it (it used to select the Java 8 engine, which is still available as java-8).

Usage

Demo:

show code

JS

import { createPlayground } from 'livecodes';

const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
createPlayground('#container', options);

TS

import { createPlayground, type EmbedOptions } from 'livecodes';

const options: EmbedOptions = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
createPlayground('#container', options);

React

import LiveCodes from 'livecodes/react';

export default function App() {
  const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
  return (<LiveCodes {...options} />);
}

Vue

<script setup>
import LiveCodes from "livecodes/vue";

const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
</script>
<template>
  <LiveCodes v-bind="options" />
</template>

Svelte

<script>
import LiveCodes from 'livecodes/svelte';

const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
</script>

<LiveCodes {...options} />

Solid

import LiveCodes from 'livecodes/solid';

export default function App() {
  const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
  return (<LiveCodes {...options} />);
}

Preact

import LiveCodes from 'livecodes/preact';

export default function App() {
  const options = {
  "config": {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  }
};
  return (<LiveCodes {...options} />);
}

Web Components

<live-codes></live-codes>

<script type="module">
  import "livecodes/web-components";

  const playground = document.querySelector("live-codes");
  playground.config = {
    "activeEditor": "script",
    "script": {
      "language": "java-wasm",
      "content": "public class BinarySearchSnippet {\n  /**\n   * Search an item with binarySearch algorithm.\n   *\n   * @param arr sorted array to search\n   * @param item an item to search\n   * @return if item is found, return the index position of the array item otherwise return -1\n   */\n\n  public static int binarySearch(int[] arr, int left, int right, int item) {\n    if (right >= left) {\n      int mid = left + (right - left) / 2;\n      if (arr[mid] == item) {\n        return mid;\n      }\n\n      if (arr[mid] > item) {\n        return binarySearch(arr, left, mid - 1, item);\n      }\n\n      return binarySearch(arr, mid + 1, right, item);\n    }\n    return -1;\n  }\n\n  public static void main(String[] args) {\n    int[] sortedArray = {1, 3, 5, 7, 9, 11, 13, 15};\n    int itemToSearch = 7;\n\n    int result = binarySearch(sortedArray, 0, sortedArray.length - 1, itemToSearch);\n\n    if (result == -1) {\n      System.out.println(\"Result: Item not found in the array.\");\n    } else {\n      System.out.println(\"Result: Item found at index -> \" + result);\n    }\n  }\n}\n"
    },
    "mode": "simple",
    "editor": "auto",
    "tools": {
      "status": "full"
    }
  };
</script>

Communication with JavaScript

The Java code runs in the context of the result page. A few helper properties and methods are available in the browser global livecodes.java object:

• livecodes.java.input: the initial standard input that is passed to the Java code.
• livecodes.java.loaded: A promise that resolves when the Java environment is loaded. Any other helpers should be used after this promise resolves.
• livecodes.java.output: the standard output.
• livecodes.java.error: the standard error.
• livecodes.java.exitCode: the exit code.
• livecodes.java.run: a function that runs the Java code with new input. This function takes a string as input and returns a promise that resolves when the Java code is done running. The promise resolves with an object containing the input, output, error, and exitCode properties.

Example:

show code

JS

import { createPlayground } from 'livecodes';

const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
createPlayground('#container', options);

TS

import { createPlayground, type EmbedOptions } from 'livecodes';

const options: EmbedOptions = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
createPlayground('#container', options);

React

import LiveCodes from 'livecodes/react';

export default function App() {
  const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
  return (<LiveCodes {...options} />);
}

Vue

<script setup>
import LiveCodes from "livecodes/vue";

const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
</script>
<template>
  <LiveCodes v-bind="options" />
</template>

Svelte

<script>
import LiveCodes from 'livecodes/svelte';

const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
</script>

<LiveCodes {...options} />

Solid

import LiveCodes from 'livecodes/solid';

export default function App() {
  const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
  return (<LiveCodes {...options} />);
}

Preact

import LiveCodes from 'livecodes/preact';

export default function App() {
  const options = {
  "template": "java",
  "params": {
    "activeEditor": "markup"
  }
};
  return (<LiveCodes {...options} />);
}

Web Components

<live-codes
  template="java"></live-codes>

<script type="module">
  import "livecodes/web-components";

  const playground = document.querySelector("live-codes");
  playground.params = {
    "activeEditor": "markup"
  };
</script>

Language Info

Name

java-wasm (alias: java)

Extension

.java

Editor

script

Compiler

A fork of teavm-javac packaging OpenJDK's javac and the TeaVM AOT compiler as WebAssembly, run in a Web Worker by @live-codes/java-wasm.

Version

teavm-javac built on TeaVM 0.14.1, with javac from OpenJDK 25.

Code Formatting

Using @wasm-fmt/clang-format, applying Google's Java style guide.

Live Reload

By default, new code changes are sent to the result page for re-evaluation without a full page reload, to avoid the need to reload the Java environment.

This behavior can be disabled by adding the code comment // __livecodes_reload__ to the code, which will force a full page reload. This comment can be added in the hiddenContent property of the editor for embedded playgrounds.

Starter Template

https://livecodes.io/?template=java

Links

• Java
• TeaVM
• teavm-javac