diff --git a/validator/src/main/java/org/mustangproject/validator/ZUGFeRDValidator.java b/validator/src/main/java/org/mustangproject/validator/ZUGFeRDValidator.java
index 0c7f99ae..6214139a 100644
--- a/validator/src/main/java/org/mustangproject/validator/ZUGFeRDValidator.java
+++ b/validator/src/main/java/org/mustangproject/validator/ZUGFeRDValidator.java
@@ -7,10 +7,9 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.StringReader;
 import java.io.StringWriter;
+import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
-import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.text.SimpleDateFormat;
@@ -26,15 +25,15 @@ import org.dom4j.DocumentHelper;
 import org.dom4j.io.OutputFormat;
 import org.dom4j.io.XMLWriter;
 import org.mustangproject.XMLTools;
-import org.riversun.bigdoc.bin.BigFileSearcher;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.xml.sax.InputSource;
 
+import com.helger.commons.io.stream.StreamHelper;
+
 import jakarta.xml.bind.DatatypeConverter;
-import jakarta.xml.bind.annotation.adapters.HexBinaryAdapter;
 
 //abstract class
 public class ZUGFeRDValidator {
@@ -75,153 +74,21 @@ public class ZUGFeRDValidator {
 		return wasCompletelyValid;
 
 	}
-
-	/***
-	 * performs a validation on the file filename
-	 *
-	 * @param filename the complete absolute filename of a PDF or XML
-	 * @return a xml string with the validation result
-	 */
-	public String validate(String filename) {
-		context.clear();
-		StringBuilder finalStringResult = new StringBuilder();
-		SimpleDateFormat isoDF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-		Date date = new Date();
-		startTime = Calendar.getInstance().getTimeInMillis();
-  	Path path = Paths.get(filename);
-		Path pathFilename = path.getFileName ();
-		if (pathFilename != null)
-		  context.setFilename(pathFilename.toString());// set filename without path
-		else
-      context.setFilename(filename);// fallback to provided name
-		finalStringResult.append("<validation filename='").append (context.getFilename()).append ("' datetime='").append (isoDF.format(date)).append ("'>");
-
-		boolean isPDF = false;
-		byte[] content = null;
-		try {
-
-			if (filename == null) {
-				optionsRecognized = false;
-				context.addResultItem(new ValidationResultItem(ESeverity.fatal, "Filename not specified").setSection(10)
-					.setPart(EPart.pdf));
-			}
-
-			PDFValidator pdfv = new PDFValidator(context);
-			File file = new File(filename);
-			if (!file.isFile()) {
-				context.addResultItem(
-					new ValidationResultItem(ESeverity.fatal, "File not found").setSection(1).setPart(EPart.pdf));
-			} else if (file.length() < 32) {
-				// with less than 32 bytes it can not even be a proper XML file
-        // Except it is "<?xml version='1.0'?><xml/>" LOL
-				context.addResultItem(
-					new ValidationResultItem(ESeverity.fatal, "File too small").setSection(5).setPart(EPart.pdf));
-			} else {
-				content = Files.readAllBytes(file.toPath());
-				XMLValidator xv = new XMLValidator(context);
-				if (disableNotices) {
-					xv.disableNotices();
-				}
-				isPDF = ByteArraySearcher.indexOf(content, new byte[] {'%', 'P', 'D', 'F'}) == 0;
-				if (isPDF) {
-					pdfv.setFilename(filename);
-					pdfv.setFileContents(content);
-
-					optionsRecognized = true;
-					finalStringResult.append("<pdf>");
-					try {
-						pdfv.validate();
-
-						sha1Checksum = calcSHA1(content);
-
-						// Validate PDF
-
-						getPdfValidationResults(finalStringResult, pdfv, xv);
-					} catch (IrrecoverableValidationError irx) {
-            LOGGER.info(irx.getMessage());
-					}
-
-					finalStringResult.append("</pdf>\n");
-
-					context.clearCustomXML();
-				} else {
-					boolean isXML = false;
-					try {
-						DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
-						DocumentBuilder db = dbf.newDocumentBuilder();
-
-						content = XMLTools.removeBOM(content);
-						String s = new String(content, StandardCharsets.UTF_8);
-						InputSource is = new InputSource(new StringReader(s));
-						Document doc = db.parse(is);
-
-						Element root = doc.getDocumentElement();
-						isXML = true;//no exception so far
-
-					} catch (Exception ex) {
-						// probably no xml file, sth like SAXParseException content not allowed in prolog
-						// ignore isXML is already false
-						// in the tests, this may error-out anyway
-					  LOGGER.info("No XML part provided");
-					}
-					if (isXML) {
-						pdfValidity = true;
-						optionsRecognized = true;
-						xv.setFilename(filename);
-						sha1Checksum = calcSHA1(content);
-
-						displayXMLValidationOutput = true;
-
-					} else {
-						optionsRecognized = false;
-						context.addResultItem(new ValidationResultItem(ESeverity.exception,
-							"File does not look like PDF nor XML (contains neither %PDF nor <?xml)").setSection(8));
-
-					}
-				}
-				if ((optionsRecognized) && (displayXMLValidationOutput)) {
-					finalStringResult.append("<xml>");
-					try {
-						xv.validate();
-					} catch (IrrecoverableValidationError irx) {
-            LOGGER.info("The hell");
-					}
-					finalStringResult.append(xv.getXMLResult());
-					finalStringResult.append("</xml>");
-					context.clearCustomXML();
-				}
-
-				if ((isPDF) && (!pdfValidity)) {
-					context.setInvalid();
-				}
-
-			}
-		} catch (IrrecoverableValidationError | IOException irx) {
-      LOGGER.info(irx.getMessage());
-      context.setInvalid ();
-		} finally {
-			finalStringResult.append(context.getXMLResult());
-			finalStringResult.append("</validation>");
-
-		}
-
-		return formatOutput(finalStringResult, isPDF);
-	}
-
-  public String validate(InputStream inputStream, String fileNameOfInputStream) {
+	
+	private String internalValidate (String contextFilename, InputStream inputStream, long inputLength) {
     context.clear();
     StringBuilder finalStringResult = new StringBuilder();
     SimpleDateFormat isoDF = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
     Date date = new Date();
     startTime = Calendar.getInstance().getTimeInMillis();
-    context.setFilename(fileNameOfInputStream);// set filename without path
-    finalStringResult.append("<validation filename='").append(context.getFilename()).append("' datetime='").append(isoDF.format(date)).append("'>");
+    context.setFilename(contextFilename);// fallback to provided name
+    finalStringResult.append("<validation filename='").append (contextFilename).append ("' datetime='").append (isoDF.format(date)).append ("'>");
 
     boolean isPDF = false;
     byte[] content = null;
     try {
 
-      if (fileNameOfInputStream == null) {
+      if (contextFilename == null || contextFilename.isEmpty ()) {
         optionsRecognized = false;
         context.addResultItem(new ValidationResultItem(ESeverity.fatal, "Filename not specified").setSection(10)
           .setPart(EPart.pdf));
@@ -231,7 +98,7 @@ public class ZUGFeRDValidator {
       if (inputStream == null) {
         context.addResultItem(
           new ValidationResultItem(ESeverity.fatal, "File not found").setSection(1).setPart(EPart.pdf));
-      } else if (inputStream.available() < 32) {
+      } else if (inputLength < 32) {
         // with less than 32 bytes it can not even be a proper XML file
         // Except it is "<?xml version='1.0'?><xml/>" LOL
         context.addResultItem(
@@ -245,7 +112,7 @@ public class ZUGFeRDValidator {
         isPDF = ByteArraySearcher.indexOf(content, new byte[] {'%', 'P', 'D', 'F'}) == 0;
         if (isPDF) {
           // Avoid reading again from file
-          pdfv.setFilenameAndContents(fileNameOfInputStream, content);
+          pdfv.setFilenameAndContents(contextFilename, content);
 
           optionsRecognized = true;
           finalStringResult.append("<pdf>");
@@ -278,6 +145,7 @@ public class ZUGFeRDValidator {
 
             Element root = doc.getDocumentElement();
             isXML = true;//no exception so far
+
           } catch (Exception ex) {
             // probably no xml file, sth like SAXParseException content not allowed in prolog
             // ignore isXML is already false
@@ -289,7 +157,7 @@ public class ZUGFeRDValidator {
             optionsRecognized = true;
             xv.setStringContent (xmlAsString);
             xv.disableAutoload();
-            xv.setFilename(fileNameOfInputStream);
+            xv.setFilename(contextFilename);
             sha1Checksum = calcSHA1(content);
 
             displayXMLValidationOutput = true;
@@ -328,6 +196,60 @@ public class ZUGFeRDValidator {
     }
 
     return formatOutput(finalStringResult, isPDF);
+	}
+
+	/***
+	 * performs a validation on the file filename
+	 *
+	 * @param filename the complete absolute filename of a PDF or XML
+	 * @return a xml string with the validation result
+	 */
+	public String validate(String filename) {
+	  String contextFilename;
+	  InputStream inputStream;
+	  long inputLength;
+	  if (filename == null) {
+	    // No filename provided
+	    contextFilename = "";
+	    inputStream = null;
+	    inputLength = 0;
+	  } else {
+      File file = new File(filename);
+      // set filename without path
+  		contextFilename = file.getName ();
+  		if (file.isFile ()) {
+  		  try {
+  		    inputStream = new FileInputStream (file);
+  		    inputLength = Files.size (file.toPath ());
+  		  } catch (IOException ex) {
+  		    throw new UncheckedIOException (ex);
+  		  }
+  		} else {
+  		  // Non-existing or Directory
+        inputStream = null;
+        inputLength = 0;
+  		}
+	  }
+  	try {
+		  return internalValidate (contextFilename, inputStream, inputLength);
+  	} finally {
+  	  StreamHelper.close (inputStream);
+  	}
+	}
+
+  public String validate(InputStream inputStream, String fileNameOfInputStream) {
+    long inputLength;
+    try {
+      inputLength = inputStream == null ? 0 : inputStream.available ();
+    }
+    catch (IOException ex) { 
+      throw new UncheckedIOException (ex);
+    }
+    try {
+      return internalValidate (fileNameOfInputStream, inputStream, inputLength);
+    } finally {
+      StreamHelper.close (inputStream);
+    }
   }
 
 	private void getPdfValidationResults(StringBuilder finalStringResult, PDFValidator pdfv, XMLValidator xv) throws IrrecoverableValidationError {
diff --git a/validator/src/test/java/org/mustangproject/validator/MiscValidatorTest.java b/validator/src/test/java/org/mustangproject/validator/MiscValidatorTest.java
index b333ce25..1243ca83 100644
--- a/validator/src/test/java/org/mustangproject/validator/MiscValidatorTest.java
+++ b/validator/src/test/java/org/mustangproject/validator/MiscValidatorTest.java
@@ -13,15 +13,15 @@ public class MiscValidatorTest extends ResourceCase  {
 		ZUGFeRDValidator zfv=new ZUGFeRDValidator();
 
 		String res=zfv.validate(null);
-		assertTrue(res.matches("<\\?xml version=\"1.0\" encoding=\"UTF-8\"\\?>\n" + 
-				"\n" + 
-				"<validation filename=\"\" datetime=\".*?\">\n" + 
-				"  <messages>\n" + 
-				"    <error type=\"10\">Filename not specified</error> \n" + 
-				"  </messages>\n" + 
-				"  <summary status=\"invalid\"/>\n" + 
-				"</validation>\n" + 
-				""));
+    assertTrue(res.matches("<\\?xml version=\"1.0\" encoding=\"UTF-8\"\\?>\n" + 
+        "\n" + 
+        "<validation filename=\"\" datetime=\".*?\">\n" + 
+        "  <messages>\n" + 
+        "    <error type=\"10\">Filename not specified</error> \n" + 
+        "  </messages>\n" + 
+        "  <summary status=\"invalid\"/>\n" + 
+        "</validation>\n" + 
+        ""));
 
 		res=zfv.validate("/dhfkbv/sfjkh");
 		assertTrue(res.matches("<\\?xml version=\"1.0\" encoding=\"UTF-8\"\\?>\n" +