diff --git a/pom.xml b/pom.xml
index c1f40f3..c439212 100644
--- a/pom.xml
+++ b/pom.xml
@@ -74,6 +74,11 @@
 			<artifactId>jackson-datatype-jsr310</artifactId>
 			<version>${jackson.version}</version>
 		</dependency>
+		<dependency>
+			<groupId>org.apache.commons</groupId>
+			<artifactId>commons-lang3</artifactId>
+			<version>3.14.0</version>
+		</dependency>
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>
diff --git a/src/main/java/com/inteligr8/rs/BasicAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/BasicAuthorizationFilter.java
index f951186..2dfc89f 100755
--- a/src/main/java/com/inteligr8/rs/BasicAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/BasicAuthorizationFilter.java
@@ -20,6 +20,8 @@ import java.util.Base64;
 import javax.ws.rs.client.ClientRequestContext;
 import javax.ws.rs.core.HttpHeaders;
 
+import org.apache.commons.lang3.StringUtils;
+
 /**
  * This class implements a simple 2-credential (username &amp; password) based
  * authorization filter.
@@ -36,8 +38,8 @@ public class BasicAuthorizationFilter implements AuthorizationFilter {
 	 * @param password A password or secret key.
 	 */
 	public BasicAuthorizationFilter(String username, String password) {
-		this.username = username;
-		this.password = password;
+		this.username = StringUtils.trimToNull(username);
+		this.password = StringUtils.trimToNull(password);
 	}
 	
 	/**
diff --git a/src/main/java/com/inteligr8/rs/ClientEnforcementAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/ClientEnforcementAuthorizationFilter.java
index c7842a1..63274e9 100644
--- a/src/main/java/com/inteligr8/rs/ClientEnforcementAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/ClientEnforcementAuthorizationFilter.java
@@ -16,6 +16,8 @@ package com.inteligr8.rs;
 
 import javax.ws.rs.client.ClientRequestContext;
 
+import org.apache.commons.lang3.StringUtils;
+
 /**
  * This class is the base for implementations of client authorization similar
  * to OAuth-based flows.
@@ -45,8 +47,8 @@ public class ClientEnforcementAuthorizationFilter implements AuthorizationFilter
 	 * @param clientSecret A secret corresponding to the client ID.
 	 */
 	public ClientEnforcementAuthorizationFilter(String clientId, String clientSecret) {
-		this.clientId = clientId;
-		this.clientSecret = clientSecret;
+		this.clientId = StringUtils.trimToNull(clientId);
+		this.clientSecret = StringUtils.trimToNull(clientSecret);
 	}
 
 	/**
diff --git a/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
index 77073bc..c1a0b93 100755
--- a/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthAuthorizationCodeAuthorizationFilter.java
@@ -18,6 +18,10 @@ import java.net.URI;
 
 import javax.ws.rs.core.Form;
 
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * This class implements the OAuth Authorization Code flow as an authorization
  * filter.
@@ -25,6 +29,8 @@ import javax.ws.rs.core.Form;
  * @author brian@inteligr8.com
  */
 public class OAuthAuthorizationCodeAuthorizationFilter extends OAuthAuthorizationFilter {
+    
+    private final Logger logger = LoggerFactory.getLogger(this.getClass());
 	
 	private final String code;
 	private final URI redirectUri;
@@ -68,12 +74,13 @@ public class OAuthAuthorizationCodeAuthorizationFilter extends OAuthAuthorizatio
 	public OAuthAuthorizationCodeAuthorizationFilter(String tokenUrl, String clientId, String clientSecret, String code, URI redirectUri) {
 		super(tokenUrl, clientId, clientSecret);
 		
-		this.code = code;
+		this.code = StringUtils.trimToNull(code);
 		this.redirectUri = redirectUri;
 	}
 	
 	@Override
 	protected Form createForm() {
+        this.logger.debug("Using OAuth grant_type 'authorization_code'");
 		Form form = new Form().param("grant_type", "authorization_code");
 		if (this.redirectUri != null)
 			form.param("redirect_uri", this.redirectUri.toString());
diff --git a/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
index cc27a43..519aaf2 100755
--- a/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthAuthorizationFilter.java
@@ -27,6 +27,7 @@ import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.Response;
 import javax.ws.rs.core.Response.Status.Family;
 
+import org.apache.commons.lang3.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -88,9 +89,9 @@ public abstract class OAuthAuthorizationFilter implements AuthorizationFilter {
 	 */
 	public OAuthAuthorizationFilter(String tokenUrl, String clientId, String clientSecret, String scope) {
 		this.tokenUrl = tokenUrl;
-		this.clientId = clientId;
-		this.clientSecret = clientSecret;
-		this.scope = scope;
+		this.clientId = StringUtils.trimToNull(clientId);
+		this.clientSecret = StringUtils.trimToNull(clientSecret);
+		this.scope = StringUtils.trimToNull(scope);
 	}
 
 	/**
diff --git a/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
index 40856e8..b6d9a97 100755
--- a/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthClientCredentialAuthorizationFilter.java
@@ -16,6 +16,9 @@ package com.inteligr8.rs;
 
 import javax.ws.rs.core.Form;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * This class implements the OAuth Client Credential flow as an authorization
  * filter.
@@ -23,6 +26,8 @@ import javax.ws.rs.core.Form;
  * @author brian@inteligr8.com
  */
 public class OAuthClientCredentialAuthorizationFilter extends OAuthAuthorizationFilter {
+    
+    private final Logger logger = LoggerFactory.getLogger(this.getClass());
 
 	/**
 	 * @param tokenUrl The URL to the OAuth IdP token service.
@@ -35,6 +40,7 @@ public class OAuthClientCredentialAuthorizationFilter extends OAuthAuthorization
 	
 	@Override
 	protected Form createForm() {
+        this.logger.debug("Using OAuth grant_type 'client_credentials'");
 		return new Form().param("grant_type", "client_credentials");
 	}
 	
diff --git a/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java b/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
index 39a1a2e..a5db103 100755
--- a/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
+++ b/src/main/java/com/inteligr8/rs/OAuthPasswordGrantAuthorizationFilter.java
@@ -16,6 +16,10 @@ package com.inteligr8.rs;
 
 import javax.ws.rs.core.Form;
 
+import org.apache.commons.lang3.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * This class implements the OAuth Password Grant flow as an authorization
  * filter.
@@ -23,6 +27,8 @@ import javax.ws.rs.core.Form;
  * @author brian@inteligr8.com
  */
 public class OAuthPasswordGrantAuthorizationFilter extends OAuthAuthorizationFilter {
+    
+    private final Logger logger = LoggerFactory.getLogger(this.getClass());
 	
 	private final String username;
 	private final String password;
@@ -46,12 +52,13 @@ public class OAuthPasswordGrantAuthorizationFilter extends OAuthAuthorizationFil
 	 */
 	public OAuthPasswordGrantAuthorizationFilter(String tokenUrl, String clientId, String clientSecret, String username, String password) {
 		super(tokenUrl, clientId, clientSecret);
-		this.username = username;
-		this.password = password;
+		this.username = StringUtils.trimToNull(username);
+		this.password = StringUtils.trimToNull(password);
 	}
 	
 	@Override
 	protected Form createForm() {
+        this.logger.debug("Using OAuth grant_type 'password': {}", this.username);
 		return new Form().param("grant_type", "password")
 				.param("username", this.username);
 	}