Fix static method declarations

- Made isInSubnet method static in DenylistFileProvider.java
- Made getZipInputStream method static in ZipFileProvider.java

These methods don't use instance variables and can be declared as static.

Author: Developer

src/main/java/de/rub/nds/crawler/denylist/DenylistFileProvider.java

@@ -58,7 +58,7 @@ public DenylistFileProvider(String denylistFilename) {
         }
     }
 
-    private boolean isInSubnet(String ip, SubnetUtils.SubnetInfo subnetInfo) {
+    private static boolean isInSubnet(String ip, SubnetUtils.SubnetInfo subnetInfo) {
         try {
             return subnetInfo.isInRange(ip);
         } catch (IllegalArgumentException e) {

src/main/java/de/rub/nds/crawler/targetlist/ZipFileProvider.java

@@ -91,7 +91,7 @@ public List<String> getTargetList() {
         return targetList;
     }
 
-    private InflaterInputStream getZipInputStream(String filename) throws IOException {
+    private static InflaterInputStream getZipInputStream(String filename) throws IOException {
         if (filename.contains(".gz")) {
             return new GZIPInputStream(new FileInputStream(filename));
         } else {