diff --git a/spring-cloud-function-context/pom.xml b/spring-cloud-function-context/pom.xml
index b2b4eefa2..960e9e5ad 100644
--- a/spring-cloud-function-context/pom.xml
+++ b/spring-cloud-function-context/pom.xml
@@ -52,6 +52,12 @@
 			<groupId>org.springframework.boot</groupId>
 			<artifactId>spring-boot-starter-test</artifactId>
 			<optional>true</optional>
+			<exclusions>
+				<exclusion>
+					<groupId>com.vaadin.external.google</groupId>
+    				<artifactId>android-json</artifactId>
+				</exclusion>
+			</exclusions>
 		</dependency>
 		<dependency>
 			<groupId>io.projectreactor</groupId>
diff --git a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
index 4125a7abe..16fe797f7 100644
--- a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
+++ b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java
@@ -42,7 +42,6 @@ import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.json.JSONObject;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -56,6 +55,7 @@ import org.springframework.cloud.function.context.FunctionProperties;
 import org.springframework.cloud.function.context.FunctionRegistration;
 import org.springframework.cloud.function.context.FunctionRegistry;
 import org.springframework.cloud.function.context.config.RoutingFunction;
+import org.springframework.cloud.function.json.JsonMapper;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.expression.Expression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
@@ -844,14 +844,8 @@ public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspect
 			String v = value instanceof byte[]
 					? new String((byte[]) value, StandardCharsets.UTF_8)
 							: (value instanceof String ? (String) value : null);
-			if (v != null) {
-				try {
-					new JSONObject(v);
-					return true;
-				}
-				catch (Exception ex) {
-					// ignore
-				}
+			if (v != null && JsonMapper.isJsonString(v)) {
+				return true;
 			}
 			return false;
 		}
diff --git a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/json/JsonMapper.java b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/json/JsonMapper.java
index bd65b15fd..73f5a9791 100644
--- a/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/json/JsonMapper.java
+++ b/spring-cloud-function-context/src/main/java/org/springframework/cloud/function/json/JsonMapper.java
@@ -23,7 +23,6 @@ import java.util.List;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.json.JSONObject;
 
 import org.springframework.core.ResolvableType;
 
@@ -64,20 +63,18 @@ public abstract class JsonMapper {
 	public abstract <T> T fromJson(Object json, Type type);
 
 	public byte[] toJson(Object value) {
-		if (value instanceof String) {
-			try {
-				new JSONObject((String) value);
-				if (logger.isDebugEnabled()) {
-					logger.debug(
-							"String already represents JSON. Skipping conversion in favor of 'getBytes(StandardCharsets.UTF_8'.");
-				}
-				return ((String) value).getBytes(StandardCharsets.UTF_8);
-			}
-			catch (Exception ex) {
-				// ignore
+		byte[] result = null;
+		if (isJsonString(value)) {
+			if (logger.isDebugEnabled()) {
+				logger.debug(
+						"String already represents JSON. Skipping conversion in favor of 'getBytes(StandardCharsets.UTF_8'.");
 			}
+			result = ((String) value).getBytes(StandardCharsets.UTF_8);
 		}
-		return null;
+		else {
+			logger.warn("Object does not represent a valid JSON. Object is: " + value);
+		}
+		return result;
 	}
 
 	/**
@@ -94,4 +91,22 @@ public abstract class JsonMapper {
 
 	public abstract String toString(Object value);
 
+	/**
+	 * Performs a simple validation on an object to see if it appears to be a JSON string.
+	 * NOTE: the validation is very rudimentary and simply checks that the object is a String and begins
+	 * and ends with matching pairs of "{}" or "[]" or "\"\"" and therefore may not handle some corner cases.
+	 * Primarily intended for internal of  the framework.
+	 * @param value candidate object to evaluate
+	 * @return true if and object appears to be a valid JSON string, otherwise false.
+	 */
+	public static boolean isJsonString(Object value) {
+		boolean isJson = false;
+		if (value instanceof String) {
+			String str = ((String) value).trim();
+			isJson = (str.startsWith("\"") && str.endsWith("\"")) ||
+					(str.startsWith("{") && str.endsWith("}")) ||
+					(str.startsWith("[") && str.endsWith("]"));
+		}
+		return isJson;
+	}
 }