diff --git a/redaction-service-v1/redaction-service-server-v1/src/main/java/com/iqser/red/service/redaction/v1/server/layoutparsing/document/graph/Boundary.java b/redaction-service-v1/redaction-service-server-v1/src/main/java/com/iqser/red/service/redaction/v1/server/layoutparsing/document/graph/Boundary.java
index 845ce384..835c08b3 100644
--- a/redaction-service-v1/redaction-service-server-v1/src/main/java/com/iqser/red/service/redaction/v1/server/layoutparsing/document/graph/Boundary.java
+++ b/redaction-service-v1/redaction-service-server-v1/src/main/java/com/iqser/red/service/redaction/v1/server/layoutparsing/document/graph/Boundary.java
@@ -140,23 +140,23 @@ public class Boundary implements Comparable<Boundary> {
 
 
     /**
-     * shrinks the boundary, such that textBlock.subSequence(boundary) returns a string without whitespaces.
+     * shrinks the boundary, such that textBlock.subSequence(boundary) returns a string without trailing or preceding whitespaces.
      *
      * @param textBlock TextBlock to check whitespaces against
-     * @return boundary
+     * @return trimmed boundary
      */
     public Boundary trim(TextBlock textBlock) {
 
-        if (textBlock.isEmpty()) {
-            return textBlock.getBoundary();
+        if (this.length() == 0) {
+            return this;
         }
         int trimmedStart = this.start;
-        while (Character.isWhitespace(textBlock.charAt(trimmedStart))) {
+        while (textBlock.containsIndex(trimmedStart) && trimmedStart < end && Character.isWhitespace(textBlock.charAt(trimmedStart))) {
             trimmedStart++;
         }
 
         int trimmedEnd = this.end;
-        while (Character.isWhitespace(textBlock.charAt(trimmedEnd - 1))) {
+        while (textBlock.containsIndex(trimmedEnd - 1) && trimmedStart < trimmedEnd && Character.isWhitespace(textBlock.charAt(trimmedEnd - 1))) {
             trimmedEnd--;
         }