Merge e53962a2a4 into 799ee7c97e

* Update the graalvm documentation

* update the documentation

README.md

@@ -118,6 +118,8 @@ Currently, the following distributions are supported:
 
 **NOTE:** For Azul Zulu OpenJDK architectures x64 and arm64 are mapped to x86 / arm with proper hw_bitness.
 
+**NOTE:** To comply with the GraalVM Free Terms and Conditions (GFTC) license, it is recommended to use GraalVM JDK 17 version 17.0.12, as this is the only version of GraalVM JDK 17 available under the GFTC license. Additionally, it is encouraged to consider upgrading to GraalVM JDK 21, which offers the latest features and improvements.
+
 ### Caching packages dependencies
 The action has a built-in functionality for caching and restoring dependencies. It uses [toolkit/cache](https://github.com/actions/toolkit/tree/main/packages/cache) under hood for caching dependencies but requires less configuration settings. Supported package managers are gradle, maven and sbt. The format of the used cache key is `setup-java-${{ platform }}-${{ packageManager }}-${{ fileHash }}`, where the hash is based on the following files:
 

__tests__/toolchains.test.ts

@@ -143,7 +143,20 @@ describe('toolchains tests', () => {
         </toolchain>
       </toolchains>`;
     const result = `<?xml version="1.0"?>
-<toolchains>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
   <toolchain>
     <type>jdk</type>
     <provides>
@@ -155,6 +168,442 @@ describe('toolchains tests', () => {
       <jdkHome>/opt/jdk/sun/1.6</jdkHome>
     </configuration>
   </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not discard custom elements in existing toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+          <type>jdk</type>
+          <provides>
+            <version>1.6</version>
+            <vendor>Sun</vendor>
+            <id>sun_1.6</id>
+            <custom>foo</custom>
+          </provides>
+          <configuration>
+            <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+            <fooHome>/usr/local/bin/bash</fooHome>
+          </configuration>
+        </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.6</version>
+      <vendor>Sun</vendor>
+      <id>sun_1.6</id>
+      <custom>foo</custom>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+      <fooHome>/usr/local/bin/bash</fooHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not discard existing, custom toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+            <type>foo</type>
+            <provides>
+                <custom>baz</custom>
+            </provides>
+            <configuration>
+                <fooHome>/usr/local/bin/foo</fooHome>
+            </configuration>
+        </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>foo</type>
+    <provides>
+      <custom>baz</custom>
+    </provides>
+    <configuration>
+      <fooHome>/usr/local/bin/foo</fooHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not duplicate existing toolchain definitions', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+      <toolchain>
+        <type>jdk</type>
+        <provides>
+          <version>17</version>
+          <vendor>Eclipse Temurin</vendor>
+          <id>temurin_17</id>
+        </provides>
+        <configuration>
+          <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+        </configuration>
+      </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('does not duplicate existing toolchain definitions if multiple exist', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+        <toolchain>
+          <type>jdk</type>
+          <provides>
+            <version>1.6</version>
+            <vendor>Sun</vendor>
+            <id>sun_1.6</id>
+          </provides>
+          <configuration>
+            <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+          </configuration>
+        </toolchain>
+      <toolchain>
+        <type>jdk</type>
+        <provides>
+          <version>17</version>
+          <vendor>Eclipse Temurin</vendor>
+          <id>temurin_17</id>
+        </provides>
+        <configuration>
+          <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+        </configuration>
+      </toolchain>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>1.6</version>
+      <vendor>Sun</vendor>
+      <id>sun_1.6</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/jdk/sun/1.6</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('handles an empty list of existing toolchains correctly', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = `<toolchains>
+      </toolchains>`;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>17</version>
+      <vendor>Eclipse Temurin</vendor>
+      <id>temurin_17</id>
+    </provides>
+    <configuration>
+      <jdkHome>/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>`;
+
+    fs.mkdirSync(m2Dir, {recursive: true});
+    fs.writeFileSync(toolchainsFile, originalFile);
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+
+    await toolchains.createToolchainsSettings({
+      jdkInfo,
+      settingsDirectory: m2Dir,
+      overwriteSettings: true
+    });
+
+    expect(fs.existsSync(m2Dir)).toBe(true);
+    expect(fs.existsSync(toolchainsFile)).toBe(true);
+    expect(fs.readFileSync(toolchainsFile, 'utf-8')).toEqual(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    );
+    expect(
+      toolchains.generateToolchainDefinition(
+        originalFile,
+        jdkInfo.version,
+        jdkInfo.vendor,
+        jdkInfo.id,
+        jdkInfo.jdkHome
+      )
+    ).toEqual(result);
+  }, 100000);
+
+  it('handles an empty existing toolchains.xml correctly', async () => {
+    const jdkInfo = {
+      version: '17',
+      vendor: 'Eclipse Temurin',
+      id: 'temurin_17',
+      jdkHome: '/opt/hostedtoolcache/Java_Temurin-Hotspot_jdk/17.0.1-12/x64'
+    };
+
+    const originalFile = ``;
+    const result = `<?xml version="1.0"?>
+<toolchains xmlns="http://maven.apache.org/TOOLCHAINS/1.1.0"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd">
   <toolchain>
     <type>jdk</type>
     <provides>

dist/setup/index.js

@@ -134858,46 +134858,53 @@ function createToolchainsSettings({ jdkInfo, settingsDirectory, overwriteSetting
 exports.createToolchainsSettings = createToolchainsSettings;
 // only exported for testing purposes
 function generateToolchainDefinition(original, version, vendor, id, jdkHome) {
-    let xmlObj;
+    let jsToolchains = [
+        {
+            type: 'jdk',
+            provides: {
+                version: `${version}`,
+                vendor: `${vendor}`,
+                id: `${id}`
+            },
+            configuration: {
+                jdkHome: `${jdkHome}`
+            }
+        }
+    ];
     if (original === null || original === void 0 ? void 0 : original.length) {
-        xmlObj = (0, xmlbuilder2_1.create)(original)
+        // convert existing toolchains into TS native objects for better handling
+        // xmlbuilder2 will convert the document into a `{toolchains: { toolchain: [] | {} }}` structure
+        // instead of the desired `toolchains: [{}]` one or simply `[{}]`
+        const jsObj = (0, xmlbuilder2_1.create)(original)
             .root()
-            .ele({
+            .toObject();
-            toolchain: {
+        if (jsObj.toolchains && jsObj.toolchains.toolchain) {
-                type: 'jdk',
+            // in case only a single child exists xmlbuilder2 will not create an array and using verbose = true equally doesn't work here
-                provides: {
+            // See https://oozcitak.github.io/xmlbuilder2/serialization.html#js-object-and-map-serializers for details
-                    version: `${version}`,
+            if (Array.isArray(jsObj.toolchains.toolchain)) {
-                    vendor: `${vendor}`,
+                jsToolchains.push(...jsObj.toolchains.toolchain);
-                    id: `${id}`
-                },
-                configuration: {
-                    jdkHome: `${jdkHome}`
-                }
             }
-        });
+            else {
+                jsToolchains.push(jsObj.toolchains.toolchain);
+            }
+        }
+        // remove potential duplicates based on type & id (which should be a unique combination);
+        // self.findIndex will only return the first occurrence, ensuring duplicates are skipped
+        jsToolchains = jsToolchains.filter((value, index, self) => 
+        // ensure non-jdk toolchains are kept in the results, we must not touch them because they belong to the user
+        value.type !== 'jdk' ||
+            index ===
+                self.findIndex(t => t.type === value.type && t.provides.id === value.provides.id));
     }
-    else
+    // TODO: technically bad because we shouldn't re-create the toolchains root node (with possibly different schema values) if it already exists, however, just overriding the toolchain array with xmlbuilder2 is … uh non-trivial
-        xmlObj = (0, xmlbuilder2_1.create)({
+    return (0, xmlbuilder2_1.create)({
-            toolchains: {
+        toolchains: {
-                '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
+            '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
-                '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
+            '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
-                '@xsi:schemaLocation': 'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
+            '@xsi:schemaLocation': 'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
-                toolchain: [
+            toolchain: jsToolchains
-                    {
+        }
-                        type: 'jdk',
+    }).end({
-                        provides: {
-                            version: `${version}`,
-                            vendor: `${vendor}`,
-                            id: `${id}`
-                        },
-                        configuration: {
-                            jdkHome: `${jdkHome}`
-                        }
-                    }
-                ]
-            }
-        });
-    return xmlObj.end({
         format: 'xml',
         wellFormed: false,
         headless: false,

src/toolchains.ts

@@ -84,47 +84,59 @@ export function generateToolchainDefinition(
   id: string,
   jdkHome: string
 ) {
-  let xmlObj;
+  let jsToolchains: Toolchain[] = [
-  if (original?.length) {
+    {
-    xmlObj = xmlCreate(original)
+      type: 'jdk',
-      .root()
+      provides: {
-      .ele({
+        version: `${version}`,
-        toolchain: {
+        vendor: `${vendor}`,
-          type: 'jdk',
+        id: `${id}`
-          provides: {
+      },
-            version: `${version}`,
+      configuration: {
-            vendor: `${vendor}`,
+        jdkHome: `${jdkHome}`
-            id: `${id}`
-          },
-          configuration: {
-            jdkHome: `${jdkHome}`
-          }
-        }
-      });
-  } else
-    xmlObj = xmlCreate({
-      toolchains: {
-        '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
-        '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
-        '@xsi:schemaLocation':
-          'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
-        toolchain: [
-          {
-            type: 'jdk',
-            provides: {
-              version: `${version}`,
-              vendor: `${vendor}`,
-              id: `${id}`
-            },
-            configuration: {
-              jdkHome: `${jdkHome}`
-            }
-          }
-        ]
       }
-    });
+    }
+  ];
+  if (original?.length) {
+    // convert existing toolchains into TS native objects for better handling
+    // xmlbuilder2 will convert the document into a `{toolchains: { toolchain: [] | {} }}` structure
+    // instead of the desired `toolchains: [{}]` one or simply `[{}]`
+    const jsObj = xmlCreate(original)
+      .root()
+      .toObject() as unknown as ExtractedToolchains;
+    if (jsObj.toolchains && jsObj.toolchains.toolchain) {
+      // in case only a single child exists xmlbuilder2 will not create an array and using verbose = true equally doesn't work here
+      // See https://oozcitak.github.io/xmlbuilder2/serialization.html#js-object-and-map-serializers for details
+      if (Array.isArray(jsObj.toolchains.toolchain)) {
+        jsToolchains.push(...jsObj.toolchains.toolchain);
+      } else {
+        jsToolchains.push(jsObj.toolchains.toolchain);
+      }
+    }
 
-  return xmlObj.end({
+    // remove potential duplicates based on type & id (which should be a unique combination);
+    // self.findIndex will only return the first occurrence, ensuring duplicates are skipped
+    jsToolchains = jsToolchains.filter(
+      (value, index, self) =>
+        // ensure non-jdk toolchains are kept in the results, we must not touch them because they belong to the user
+        value.type !== 'jdk' ||
+        index ===
+          self.findIndex(
+            t => t.type === value.type && t.provides.id === value.provides.id
+          )
+    );
+  }
+
+  // TODO: technically bad because we shouldn't re-create the toolchains root node (with possibly different schema values) if it already exists, however, just overriding the toolchain array with xmlbuilder2 is … uh non-trivial
+  return xmlCreate({
+    toolchains: {
+      '@xmlns': 'http://maven.apache.org/TOOLCHAINS/1.1.0',
+      '@xmlns:xsi': 'http://www.w3.org/2001/XMLSchema-instance',
+      '@xsi:schemaLocation':
+        'http://maven.apache.org/TOOLCHAINS/1.1.0 https://maven.apache.org/xsd/toolchains-1.1.0.xsd',
+      toolchain: jsToolchains
+    }
+  }).end({
     format: 'xml',
     wellFormed: false,
     headless: false,
@@ -167,3 +179,22 @@ async function writeToolchainsFileToDisk(
     flag: 'w'
   });
 }
+
+interface ExtractedToolchains {
+  toolchains: {
+    toolchain: Toolchain[] | Toolchain;
+  };
+}
+
+// Toolchain type definition according to Maven Toolchains XSD 1.1.0
+interface Toolchain {
+  type: string;
+  provides:
+    | {
+        version: string;
+        vendor: string;
+        id: string;
+      }
+    | any;
+  configuration: any;
+}