Consistent use of JDK 7 AssertionError with root cause

Issue: SPR-13188

spring-test/src/main/java/org/springframework/test/util/JsonPathExpectationsHelper.java

@@ -237,22 +237,22 @@ public class JsonPathExpectationsHelper {
 	}
 
 	private Object evaluateJsonPath(String content) {
-		String message = "No value at JSON path \"" + this.expression + "\", exception: ";
+		String message = "No value at JSON path \"" + this.expression + "\"";
 		try {
 			return this.jsonPath.read(content);
 		}
 		catch (Throwable ex) {
-			throw new AssertionError(message + ex.getMessage());
+			throw new AssertionError(message, ex);
 		}
 	}
 
 	private Object evaluateJsonPath(String content, Class<?> targetType) {
-		String message = "No value at JSON path \"" + this.expression + "\", exception: ";
+		String message = "No value at JSON path \"" + this.expression + "\"";
 		try {
 			return JsonPath.parse(content).read(this.expression, targetType);
 		}
 		catch (Throwable ex) {
-			throw new AssertionError(message + ex.getMessage());
+			throw new AssertionError(message, ex);
 		}
 	}
 

spring-test/src/main/java/org/springframework/test/web/client/match/ContentRequestMatchers.java

@@ -223,7 +223,7 @@ public class ContentRequestMatchers {
 				matchInternal(mockRequest);
 			}
 			catch (Exception ex) {
-				throw new AssertionError("Failed to parse expected or actual XML request content: " + ex.getMessage());
+				throw new AssertionError("Failed to parse expected or actual XML request content", ex);
 			}
 		}
 

spring-test/src/main/java/org/springframework/test/web/client/match/JsonPathRequestMatchers.java

@@ -252,7 +252,7 @@ public class JsonPathRequestMatchers {
 				matchInternal(mockRequest);
 			}
 			catch (ParseException ex) {
-				throw new AssertionError("Failed to parse JSON request content: " + ex.getMessage());
+				throw new AssertionError("Failed to parse JSON request content", ex);
 			}
 		}
 

spring-test/src/main/java/org/springframework/test/web/client/match/XpathRequestMatchers.java

@@ -194,7 +194,7 @@ public class XpathRequestMatchers {
 				matchInternal(mockRequest);
 			}
 			catch (Exception ex) {
-				throw new AssertionError("Failed to parse XML request content: " + ex.getMessage());
+				throw new AssertionError("Failed to parse XML request content", ex);
 			}
 		}
 

spring-test/src/main/java/org/springframework/test/web/servlet/result/JsonPathResultMatchers.java

@@ -258,9 +258,8 @@ public class JsonPathResultMatchers {
 				MatcherAssert.assertThat(reason, content, StringStartsWith.startsWith(this.prefix));
 				return content.substring(this.prefix.length());
 			}
-			catch (StringIndexOutOfBoundsException oobe) {
-				throw new AssertionError(
-						"JSON prefix \"" + this.prefix + "\" not found, exception: " + oobe.getMessage());
+			catch (StringIndexOutOfBoundsException ex) {
+				throw new AssertionError("JSON prefix \"" + this.prefix + "\" not found", ex);
 			}
 		}
 		else {