Add final modifier to private fields.
diff --git a/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java b/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
index 3ea9369..0e47f8c 100644
--- a/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
+++ b/src/main/java/org/apache/commons/compress/archivers/sevenz/SevenZFile.java
@@ -77,7 +77,7 @@
     private InputStream currentFolderInputStream = null;
     private byte[] password;
 
-    private ArrayList<InputStream> deferredBlockStreams = new ArrayList<InputStream>();
+    private final ArrayList<InputStream> deferredBlockStreams = new ArrayList<InputStream>();
 
     static final byte[] sevenZSignature = {
         (byte)'7', (byte)'z', (byte)0xBC, (byte)0xAF, (byte)0x27, (byte)0x1C
diff --git a/src/test/java/org/apache/commons/compress/ArchiveReadTest.java b/src/test/java/org/apache/commons/compress/ArchiveReadTest.java
index e8a3a4b..9f67273 100644
--- a/src/test/java/org/apache/commons/compress/ArchiveReadTest.java
+++ b/src/test/java/org/apache/commons/compress/ArchiveReadTest.java
@@ -51,7 +51,7 @@
     private static final File ARCDIR = new File(CLASSLOADER.getResource("archives").getFile());
     private static final ArrayList<String> FILELIST = new ArrayList<String>();
 
-    private File file;
+    private final File file;
 
     public ArchiveReadTest(String file){
         this.file = new File(ARCDIR, file);
diff --git a/src/test/java/org/apache/commons/compress/archivers/LongPathTest.java b/src/test/java/org/apache/commons/compress/archivers/LongPathTest.java
index 3aa423d..4f4d8ba 100644
--- a/src/test/java/org/apache/commons/compress/archivers/LongPathTest.java
+++ b/src/test/java/org/apache/commons/compress/archivers/LongPathTest.java
@@ -58,7 +58,7 @@
     private static final File ARCDIR = new File(CLASSLOADER.getResource("longpath").getFile());
     private static final ArrayList<String> FILELIST = new ArrayList<String>();
 
-    private File file;
+    private final File file;
 
     public LongPathTest(String file){
         this.file = new File(ARCDIR, file);
diff --git a/src/test/java/org/apache/commons/compress/archivers/LongSymLinkTest.java b/src/test/java/org/apache/commons/compress/archivers/LongSymLinkTest.java
index 6ae4aa8..5395588 100644
--- a/src/test/java/org/apache/commons/compress/archivers/LongSymLinkTest.java
+++ b/src/test/java/org/apache/commons/compress/archivers/LongSymLinkTest.java
@@ -58,7 +58,7 @@
     private static final File ARCDIR = new File(CLASSLOADER.getResource("longsymlink").getFile());
     private static final ArrayList<String> FILELIST = new ArrayList<String>();
 
-    private File file;
+    private final File file;
 
     public LongSymLinkTest(String file){
         this.file = new File(ARCDIR, file);