diff --git a/wise-webapp/src/main/java/com/wisemapping/util/UserAgent.java b/wise-webapp/src/main/java/com/wisemapping/util/UserAgent.java
index 58448d23..fb0b5780 100644
--- a/wise-webapp/src/main/java/com/wisemapping/util/UserAgent.java
+++ b/wise-webapp/src/main/java/com/wisemapping/util/UserAgent.java
@@ -57,164 +57,169 @@ package com.wisemapping.util;
  * <a href="http://blogs.msdn.com/iemobile/archive/2006/08/03/Detecting_IE_Mobile.aspx">Detecting Internet Explorer Mobile's User-Agent on the server</a>
  */
 
+import org.jetbrains.annotations.Nullable;
+
 /**
  * @author harald
- *
  */
-public class UserAgent
-{
-	
-	private OperatingSystem operatingSystem = OperatingSystem.UNKNOWN;
-	private Browser browser = Browser.UNKNOWN;
-	private int id;
-	private String userAgentString;
-		
-	public UserAgent(OperatingSystem operatingSystem, Browser browser)
-	{
-		this.operatingSystem = operatingSystem;
-		this.browser = browser;
-		this.id = (( operatingSystem.getId() << 16) + browser.getId());
-	}
-	
-	public UserAgent(String userAgentString)
-	{
-		Browser browser = Browser.parseUserAgentString(userAgentString);
-		
-		OperatingSystem operatingSystem = OperatingSystem.UNKNOWN;
-		
-		// BOTs don't have an interesting OS for us
-		if (browser != Browser.BOT)
-			operatingSystem = OperatingSystem.parseUserAgentString(userAgentString);
-		
-		this.operatingSystem = operatingSystem;
-		this.browser = browser;
-		this.id = (( operatingSystem.getId() << 16) + browser.getId());
-		this.userAgentString = userAgentString;
-	}
+public class UserAgent {
 
-	
-	/**
-	 * @param userAgentString
-	 * @return UserAgent
-	 */
-	public static UserAgent parseUserAgentString(String userAgentString) {		
-		return new UserAgent(userAgentString);
-	}
-	
+    private OperatingSystem operatingSystem = OperatingSystem.UNKNOWN;
+    private Browser browser = Browser.UNKNOWN;
+    private int id;
+    private String userAgentString;
 
-	/**
-	 * Detects the detailed version information of the browser. Depends on the userAgent to be available. 
-	 * Use it only after using UserAgent(String) or UserAgent.parseUserAgent(String). 
-	 * Returns null if it can not detect the version information.
-	 * @return Version
-	 */
-	public Version getBrowserVersion() {
-		return this.browser.getVersion(this.userAgentString);
-	}
-	
-	/**
-	 * @return the system
-	 */
-	public OperatingSystem getOperatingSystem() {
-		return operatingSystem;
-	}
+    public UserAgent(OperatingSystem operatingSystem, Browser browser) {
+        this.operatingSystem = operatingSystem;
+        this.browser = browser;
+        this.id = ((operatingSystem.getId() << 16) + browser.getId());
+    }
 
-	/**
-	 * @return the browser
-	 */
-	public Browser getBrowser() {
-		return browser;
-	}
+    public UserAgent(@Nullable String userAgentString) {
+        if (userAgentString != null) {
+            Browser browser = Browser.parseUserAgentString(userAgentString);
 
-	/**
-	 * Returns an unique integer value of the operating system & browser combination
-	 * @return the id
-	 */
-	public int getId() {
-		return id;
-	}
+            OperatingSystem operatingSystem = OperatingSystem.UNKNOWN;
 
-	/**
-	 * Combined string representation of both enums
-	 */
-	public String toString() {
-		return this.operatingSystem.toString() + "-" + this.browser.toString();
-	}
-	
-	/**
-	 * Returns UserAgent based on specified unique id
-	 * @param id
-	 * @return
-	 */
-	public static UserAgent valueOf(int id)
-	{
-		OperatingSystem operatingSystem = OperatingSystem.valueOf((short) (id >> 16));
-		Browser browser = Browser.valueOf( (short) (id & 0x0FFFF));
-		return new UserAgent(operatingSystem,browser);
-	}
-	
-	/**
-	 * Returns UserAgent based on combined string representation
-	 * @param name
-	 * @return
-	 */
-	public static UserAgent valueOf(String name)
-	{
-		if (name == null)
+            // BOTs don't have an interesting OS for us
+            if (browser != Browser.BOT)
+                operatingSystem = OperatingSystem.parseUserAgentString(userAgentString);
+
+            this.operatingSystem = operatingSystem;
+            this.browser = browser;
+            this.id = ((operatingSystem.getId() << 16) + browser.getId());
+            this.userAgentString = userAgentString;
+
+        } else {
+            this.operatingSystem = OperatingSystem.UNKNOWN;
+            this.browser = Browser.UNKNOWN;
+        }
+    }
+
+
+    /**
+     * @param userAgentString
+     * @return UserAgent
+     */
+    public static UserAgent parseUserAgentString(String userAgentString) {
+        return new UserAgent(userAgentString);
+    }
+
+
+    /**
+     * Detects the detailed version information of the browser. Depends on the userAgent to be available.
+     * Use it only after using UserAgent(String) or UserAgent.parseUserAgent(String).
+     * Returns null if it can not detect the version information.
+     *
+     * @return Version
+     */
+    public Version getBrowserVersion() {
+        return this.browser.getVersion(this.userAgentString);
+    }
+
+    /**
+     * @return the system
+     */
+    public OperatingSystem getOperatingSystem() {
+        return operatingSystem;
+    }
+
+    /**
+     * @return the browser
+     */
+    public Browser getBrowser() {
+        return browser;
+    }
+
+    /**
+     * Returns an unique integer value of the operating system & browser combination
+     *
+     * @return the id
+     */
+    public int getId() {
+        return id;
+    }
+
+    /**
+     * Combined string representation of both enums
+     */
+    public String toString() {
+        return this.operatingSystem.toString() + "-" + this.browser.toString();
+    }
+
+    /**
+     * Returns UserAgent based on specified unique id
+     *
+     * @param id
+     * @return
+     */
+    public static UserAgent valueOf(int id) {
+        OperatingSystem operatingSystem = OperatingSystem.valueOf((short) (id >> 16));
+        Browser browser = Browser.valueOf((short) (id & 0x0FFFF));
+        return new UserAgent(operatingSystem, browser);
+    }
+
+    /**
+     * Returns UserAgent based on combined string representation
+     *
+     * @param name
+     * @return
+     */
+    public static UserAgent valueOf(String name) {
+        if (name == null)
             throw new NullPointerException("Name is null");
-		
-		String[] elements = name.split("-");
-		
-		if (elements.length == 2)
-		{
-			OperatingSystem operatingSystem = OperatingSystem.valueOf(elements[0]);
-			Browser browser = Browser.valueOf(elements[1]);
-			return new UserAgent(operatingSystem,browser);
-		}
-		
-		throw new IllegalArgumentException(
-	            "Invalid string for userAgent " + name);
-	}
 
-	/* (non-Javadoc)
-	 * @see java.lang.Object#hashCode()
-	 */
-	@Override
-	public int hashCode() {
-		final int prime = 31;
-		int result = 1;
-		result = prime * result + ((browser == null) ? 0 : browser.hashCode());
-		result = prime * result + id;
-		result = prime * result
-				+ ((operatingSystem == null) ? 0 : operatingSystem.hashCode());
-		return result;
-	}
+        String[] elements = name.split("-");
+
+        if (elements.length == 2) {
+            OperatingSystem operatingSystem = OperatingSystem.valueOf(elements[0]);
+            Browser browser = Browser.valueOf(elements[1]);
+            return new UserAgent(operatingSystem, browser);
+        }
+
+        throw new IllegalArgumentException(
+                "Invalid string for userAgent " + name);
+    }
+
+    /* (non-Javadoc)
+      * @see java.lang.Object#hashCode()
+      */
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((browser == null) ? 0 : browser.hashCode());
+        result = prime * result + id;
+        result = prime * result
+                + ((operatingSystem == null) ? 0 : operatingSystem.hashCode());
+        return result;
+    }
+
+    /* (non-Javadoc)
+      * @see java.lang.Object#equals(java.lang.Object)
+      */
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        final UserAgent other = (UserAgent) obj;
+        if (browser == null) {
+            if (other.browser != null)
+                return false;
+        } else if (!browser.equals(other.browser))
+            return false;
+        if (id != other.id)
+            return false;
+        if (operatingSystem == null) {
+            if (other.operatingSystem != null)
+                return false;
+        } else if (!operatingSystem.equals(other.operatingSystem))
+            return false;
+        return true;
+    }
 
-	/* (non-Javadoc)
-	 * @see java.lang.Object#equals(java.lang.Object)
-	 */
-	@Override
-	public boolean equals(Object obj) {
-		if (this == obj)
-			return true;
-		if (obj == null)
-			return false;
-		if (getClass() != obj.getClass())
-			return false;
-		final UserAgent other = (UserAgent) obj;
-		if (browser == null) {
-			if (other.browser != null)
-				return false;
-		} else if (!browser.equals(other.browser))
-			return false;
-		if (id != other.id)
-			return false;
-		if (operatingSystem == null) {
-			if (other.operatingSystem != null)
-				return false;
-		} else if (!operatingSystem.equals(other.operatingSystem))
-			return false;
-		return true;
-	}	
-	
 }