fixes coverity issue 141860

main/frontend-webdav/src/main/java/org/cryptomator/frontend/webdav/mount/WindowsDriveLetters.java

@@ -9,11 +9,11 @@
 package org.cryptomator.frontend.webdav.mount;
 
 import static java.util.stream.Collectors.toSet;
-import static java.util.stream.IntStream.rangeClosed;
 
 import java.nio.file.FileSystems;
 import java.nio.file.Path;
 import java.util.Set;
+import java.util.stream.IntStream;
 import java.util.stream.StreamSupport;
 
 import javax.inject.Inject;
@@ -24,16 +24,21 @@ import org.apache.commons.lang3.SystemUtils;
 
 import com.google.common.collect.Sets;
 
-
 @Singleton
 public final class WindowsDriveLetters {
-	
-	private static final Set<Character> A_TO_Z = rangeClosed('A', 'Z').mapToObj(i -> (char) i).collect(toSet());
-	
+
+	private static final Set<Character> A_TO_Z;
+
+	static {
+		try (IntStream stream = IntStream.rangeClosed('A', 'Z')) {
+			A_TO_Z = stream.mapToObj(i -> (char) i).collect(toSet());
+		}
+	}
+
 	@Inject
 	public WindowsDriveLetters() {
 	}
-	
+
 	public Set<Character> getOccupiedDriveLetters() {
 		if (!SystemUtils.IS_OS_WINDOWS) {
 			throw new UnsupportedOperationException("This method is only defined for Windows file systems");
@@ -41,7 +46,7 @@ public final class WindowsDriveLetters {
 		Iterable<Path> rootDirs = FileSystems.getDefault().getRootDirectories();
 		return StreamSupport.stream(rootDirs.spliterator(), false).map(Path::toString).map(CharUtils::toChar).map(Character::toUpperCase).collect(toSet());
 	}
-	
+
 	public Set<Character> getAvailableDriveLetters() {
 		return Sets.difference(A_TO_Z, getOccupiedDriveLetters());
 	}