diff --git a/.github/workflows/ci-check-no-dist-update.yml b/.github/workflows/ci-check-no-dist-update.yml
index f48a095..302c103 100644
--- a/.github/workflows/ci-check-no-dist-update.yml
+++ b/.github/workflows/ci-check-no-dist-update.yml
@@ -35,6 +35,6 @@ jobs:
         done
 
     - run: |
-        echo "The 'dist' directory is auotmatically updated by the release process."
+        echo "The 'dist' directory is automatically updated by the release process."
         echo "It should not be updated manually in a non-release branch or a pull request."
         exit 1
diff --git a/sources/src/caching/gradle-user-home-cache.ts b/sources/src/caching/gradle-user-home-cache.ts
index 48d8fdf..2984090 100644
--- a/sources/src/caching/gradle-user-home-cache.ts
+++ b/sources/src/caching/gradle-user-home-cache.ts
@@ -9,7 +9,7 @@ import {CacheListener} from './cache-reporting'
 import {saveCache, restoreCache, cacheDebug, isCacheDebuggingEnabled, tryDelete} from './cache-utils'
 import {CacheConfig} from '../configuration'
 import {GradleHomeEntryExtractor, ConfigurationCacheEntryExtractor} from './gradle-home-extry-extractor'
-import {getPredefinedToolchains, readResourceFileAsString} from './gradle-user-home-utils'
+import {getPredefinedToolchains, mergeToolchainContent, readResourceFileAsString} from './gradle-user-home-utils'
 
 const RESTORED_CACHE_KEY_KEY = 'restored-cache-key'
 
@@ -233,8 +233,7 @@ export class GradleUserHomeCache {
         } else {
             // Merge into an existing toolchains.xml file
             const existingToolchainContent = fs.readFileSync(toolchainXmlTarget, 'utf8')
-            const appendedContent = preInstalledToolchains.split('<toolchains>').pop()!
-            const mergedContent = existingToolchainContent.replace('</toolchains>', appendedContent)
+            const mergedContent = mergeToolchainContent(existingToolchainContent, preInstalledToolchains)
 
             fs.writeFileSync(toolchainXmlTarget, mergedContent)
             core.info(`Merged default JDK locations into ${toolchainXmlTarget}`)
diff --git a/sources/src/caching/gradle-user-home-utils.ts b/sources/src/caching/gradle-user-home-utils.ts
index d0ec406..4d38033 100644
--- a/sources/src/caching/gradle-user-home-utils.ts
+++ b/sources/src/caching/gradle-user-home-utils.ts
@@ -42,3 +42,8 @@ export function getPredefinedToolchains(): string | null {
     toolchainsXml += `</toolchains>\n`
     return toolchainsXml
 }
+
+export function mergeToolchainContent(existingToolchainContent: string, preInstalledToolchains: string): string {
+    const appendedContent = preInstalledToolchains.split('<toolchains>').pop()!
+    return existingToolchainContent.replace('</toolchains>', appendedContent)
+}
diff --git a/sources/test/jest/predefined-toolchains.test.ts b/sources/test/jest/predefined-toolchains.test.ts
index 0d8221d..6f88a03 100644
--- a/sources/test/jest/predefined-toolchains.test.ts
+++ b/sources/test/jest/predefined-toolchains.test.ts
@@ -1,4 +1,4 @@
-import {getPredefinedToolchains} from "../../src/caching/gradle-user-home-utils";
+import {getPredefinedToolchains, mergeToolchainContent} from "../../src/caching/gradle-user-home-utils";
 
 describe('predefined-toolchains', () => {
     const OLD_ENV = process.env
@@ -62,4 +62,56 @@ describe('predefined-toolchains', () => {
 `)
         })
     })
+
+    it("merges with existing toolchains", async () => {
+        jest.resetModules()
+        process.env = {
+            "JAVA_HOME_11_X64": "/jdks/foo_11",
+        }
+
+        // language=XML
+        const existingToolchains =
+            `<?xml version="1.0" encoding="UTF-8"?>
+<toolchains>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>8</version>
+    </provides>
+    <configuration>
+      <jdkHome>\${env.JAVA_HOME_8_X64}</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>
+`
+
+        const mergedContent = mergeToolchainContent(existingToolchains, getPredefinedToolchains()!)
+        expect(mergedContent).toBe(
+            // language=XML
+            `<?xml version="1.0" encoding="UTF-8"?>
+<toolchains>
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>8</version>
+    </provides>
+    <configuration>
+      <jdkHome>\${env.JAVA_HOME_8_X64}</jdkHome>
+    </configuration>
+  </toolchain>
+
+<!-- JDK Toolchains installed by default on GitHub-hosted runners -->
+  <toolchain>
+    <type>jdk</type>
+    <provides>
+      <version>11</version>
+    </provides>
+    <configuration>
+      <jdkHome>\${env.JAVA_HOME_11_X64}</jdkHome>
+    </configuration>
+  </toolchain>
+</toolchains>
+
+`)
+    })
 })