diff --git a/build.gradle.kts b/build.gradle.kts
index 918f789..6e0cabd 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -71,7 +71,7 @@ repositories {
     mavenCentral()
 }
 
-version = System.getenv().getOrDefault("VERSION", "2.10.1")
+version = System.getenv().getOrDefault("VERSION", "2.11.0")
 
 dependencies {
     implementation(group = "com.fasterxml.jackson.core", name = "jackson-core", version = "2.11.1")
diff --git a/src/main/java/net/flintmc/gradle/maven/MavenArtifactDownloader.java b/src/main/java/net/flintmc/gradle/maven/MavenArtifactDownloader.java
index 0cdb4fb..1c9331c 100644
--- a/src/main/java/net/flintmc/gradle/maven/MavenArtifactDownloader.java
+++ b/src/main/java/net/flintmc/gradle/maven/MavenArtifactDownloader.java
@@ -60,7 +60,9 @@ public MavenArtifactDownloader() {
    * @param source The repository to add
    */
   public void addSource(ReadableMavenRepository source) {
-    this.sources.add(source);
+    synchronized (this.sources) {
+      this.sources.add(source);
+    }
   }
 
   /**
@@ -70,7 +72,9 @@ public void addSource(ReadableMavenRepository source) {
    * @return {@code true} if this downloader has the give repository as a source, {@code false} otherwise
    */
   public boolean hasSource(ReadableMavenRepository source) {
-    return this.sources.contains(source);
+    synchronized (this.sources) {
+      return this.sources.contains(source);
+    }
   }
 
   /**
@@ -79,7 +83,9 @@ public boolean hasSource(ReadableMavenRepository source) {
    * @param source The repository to remove
    */
   public void removeSource(ReadableMavenRepository source) {
-    this.sources.remove(source);
+    synchronized (this.sources) {
+      this.sources.remove(source);
+  }
   }
 
   /**
@@ -97,7 +103,7 @@ public void installAll(MavenArtifact artifact, SimpleMavenRepository target, boo
     Path localPomPath = target.getPomPath(artifact);
 
     MavenPom artifactPom;
-    if(artifact instanceof MavenPom) {
+    if (artifact instanceof MavenPom) {
       // If the artifact is a POM already, don't try to read it from anywhere
       artifactPom = (MavenPom) artifact;
     } else {
@@ -105,21 +111,21 @@ public void installAll(MavenArtifact artifact, SimpleMavenRepository target, boo
       artifactPom = Files.exists(localPomPath) ? PomReader.read(localPomPath) : findPom(artifact);
     }
 
-    if(artifactPom != null) {
+    if (artifactPom != null) {
       // POM found, install it with all its dependencies
       installAll(artifactPom, target);
 
-      if(installIfNotExists) {
-        if(!Files.exists(localPomPath)) {
+      if (installIfNotExists) {
+        if (!Files.exists(localPomPath)) {
           // The POM file does not exist locally, write it down
           PomWriter.write(artifactPom, localPomPath);
         }
       }
     }
 
-    if(installIfNotExists) {
+    if (installIfNotExists) {
       // If the artifact is not installed locally, try to install it
-      if(!target.isInstalled(artifact) && !installArtifact(artifact, target) && artifactPom == null) {
+      if (!target.isInstalled(artifact) && !installArtifact(artifact, target) && artifactPom == null) {
         // The artifact failed to install and there was also no POM for it
         throw new MavenResolveException("Could not resolve " + artifact);
       }
@@ -141,19 +147,19 @@ private void installAll(MavenPom pom, SimpleMavenRepository target) throws IOExc
     Set<MavenDependency> toProcess = new HashSet<>(pom.getDependencies());
 
     // Process until the list to process is empty
-    while(!toProcess.isEmpty()) {
+    while (!toProcess.isEmpty()) {
       // Copy over the dependencies to process into the current processing round
       Set<MavenDependency> roundDependencies = new HashSet<>(toProcess);
       toProcess.clear();
 
-      for(MavenDependency dependency : roundDependencies) {
+      for (MavenDependency dependency : roundDependencies) {
         // Mark the dependency as found
         dependencies.add(dependency);
 
         // Sort out unwanted dependencies
-        if(shouldSkip(dependency)) {
+        if (shouldSkip(dependency)) {
           continue;
-        } else if(dependency.isBroken()) {
+        } else if (dependency.isBroken()) {
           continue;
         }
 
@@ -162,30 +168,30 @@ private void installAll(MavenPom pom, SimpleMavenRepository target) throws IOExc
 
         // Try to read the POM locally, if it does not exist fall back to reading it online
         MavenPom dependencyPom = Files.exists(localPomPath) ? PomReader.read(localPomPath) : findPom(dependency);
-        if(dependencyPom != null) {
+        if (dependencyPom != null) {
           // A POM file was found, iterate its dependencies
-          for(MavenDependency innerDependency : dependencyPom.getDependencies()) {
+          for (MavenDependency innerDependency : dependencyPom.getDependencies()) {
             // Sort out unwanted dependencies
-            if(shouldSkip(innerDependency)) {
+            if (shouldSkip(innerDependency)) {
               continue;
-            } else if(innerDependency.isBroken()) {
+            } else if (innerDependency.isBroken()) {
               continue;
             }
 
-            if(!dependencies.contains(innerDependency)) {
+            if (!dependencies.contains(innerDependency)) {
               // The dependency has not been found already, process it
               toProcess.add(innerDependency);
             }
           }
 
-          if(!Files.exists(localPomPath)) {
+          if (!Files.exists(localPomPath)) {
             // If the POM does not exist locally, install it
             PomWriter.write(dependencyPom, localPomPath);
           }
         }
 
         // Try to install the dependency locally
-        if(!target.isInstalled(dependency) && !installArtifact(dependency, target) && dependencyPom == null) {
+        if (!target.isInstalled(dependency) && !installArtifact(dependency, target) && dependencyPom == null) {
           // The dependency had no artifact and also no POM
           throw new MavenResolveException("Could not resolve " + dependency);
         }
@@ -213,16 +219,18 @@ private boolean shouldSkip(MavenDependency dependency) {
    * @throws IOException If an I/O error occurs while opening the stream
    */
   public InputStream findArtifactStream(MavenArtifact artifact) throws IOException {
-    for(ReadableMavenRepository source : sources) {
-      InputStream stream;
-      if((stream = source.getArtifactStream(artifact)) != null) {
-        // Found the requested artifact
-        return stream;
+    synchronized (this.sources) {
+      for (ReadableMavenRepository source : sources) {
+        InputStream stream;
+        if ((stream = source.getArtifactStream(artifact)) != null) {
+          // Found the requested artifact
+          return stream;
+        }
       }
-    }
 
-    // Artifact has not been found in any source
-    return null;
+      // Artifact has not been found in any source
+      return null;
+    }
   }
 
   /**
@@ -233,15 +241,17 @@ public InputStream findArtifactStream(MavenArtifact artifact) throws IOException
    * @throws IOException If an I/O error occurs while checking for the artifact
    */
   public Pair<ReadableMavenRepository, URI> findArtifactURI(MavenArtifact artifact) throws IOException {
-    for(ReadableMavenRepository source : sources) {
-      URI uri = source.getArtifactURI(artifact);
-      if(uri != null) {
-        return new Pair<>(source, uri);
+    synchronized (this.sources) {
+      for (ReadableMavenRepository source : sources) {
+        URI uri = source.getArtifactURI(artifact);
+        if (uri != null) {
+          return new Pair<>(source, uri);
+        }
       }
-    }
 
-    // Artifact has not been found in any source
-    return null;
+      // Artifact has not been found in any source
+      return null;
+    }
   }
 
   /**
@@ -252,11 +262,13 @@ public Pair<ReadableMavenRepository, URI> findArtifactURI(MavenArtifact artifact
    * @throws IOException If an I/O error occurs while trying to read a POM
    */
   private MavenPom findPom(MavenArtifact artifact) throws IOException {
-    for(ReadableMavenRepository source : sources) {
-      MavenPom pom;
-      if((pom = source.getArtifactPom(artifact)) != null) {
-        // Found the requested POM
-        return pom;
+    synchronized (this.sources) {
+      for (ReadableMavenRepository source : sources) {
+        MavenPom pom;
+        if ((pom = source.getArtifactPom(artifact)) != null) {
+          // Found the requested POM
+          return pom;
+        }
       }
     }
 
@@ -274,12 +286,12 @@ private MavenPom findPom(MavenArtifact artifact) throws IOException {
    */
   @SuppressWarnings("BooleanMethodIsAlwaysInverted")
   public boolean installArtifact(MavenArtifact artifact, SimpleMavenRepository target) throws IOException {
-    try(InputStream stream = findArtifactStream(artifact)) {
+    try (InputStream stream = findArtifactStream(artifact)) {
       // Try to find the given artifact
-      if(stream != null) {
+      if (stream != null) {
         // The artifact has been found, install it
         Path targetPath = target.getArtifactPath(artifact);
-        if(!Files.isDirectory(targetPath.getParent())) {
+        if (!Files.isDirectory(targetPath.getParent())) {
           // Make sure the parent directories exist
           Files.createDirectories(targetPath.getParent());
         }