improve some error messages

also, tell StringType know how to convert ints and longs

hibernate-core/src/main/java/org/hibernate/loader/internal/IdentifierLoadAccessImpl.java

@@ -173,7 +173,14 @@ protected final T doLoad(Object id) {
 
 		final JpaCompliance jpaCompliance = session.getFactory().getSessionFactoryOptions().getJpaCompliance();
 		if ( ! jpaCompliance.isLoadByIdComplianceEnabled() ) {
-			id = entityPersister.getIdentifierMapping().getJavaType().coerce( id, this );
+			try {
+				id = entityPersister.getIdentifierMapping().getJavaType().coerce( id, this );
+			}
+			catch ( Exception e ) {
+				throw new IllegalArgumentException( "Argument '" + id
+						+ "' could not be converted to the identifier type of entity '" + entityPersister.getEntityName() + "'"
+						+ " [" + e.getMessage() + "]", e );
+			}
 		}
 
 		String entityName = entityPersister.getEntityName();

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/ByteJavaType.java

@@ -169,7 +169,7 @@ public <X> Byte coerce(X value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Byte",
+						"Cannot coerce value '%s' [%s] to Byte",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/DoubleJavaType.java

@@ -201,7 +201,7 @@ public <X> Double coerce(X value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Double",
+						"Cannot coerce value '%s' [%s] to Double",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/FloatJavaType.java

@@ -196,7 +196,7 @@ public <X> Float coerce(X value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Float",
+						"Cannot coerce value '%s' [%s] to Float",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/IntegerJavaType.java

@@ -187,7 +187,7 @@ public Integer coerce(Object value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Integer",
+						"Cannot coerce value '%s' [%s] to Integer",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/JavaTypeHelper.java

@@ -15,13 +15,17 @@
 public class JavaTypeHelper {
 	protected static <T extends JavaType<?>> HibernateException unknownUnwrap(Class<?> sourceType, Class<?> targetType, T jtd) {
 		throw new HibernateException(
-				"Unknown unwrap conversion requested: " + sourceType.getName() + " to " + targetType.getName() + " : `" + jtd.getClass().getName() + "` (" + jtd.getJavaTypeClass().getName() + ")"
+				"Could not convert '" + sourceType.getName()
+						+ "' to '" + targetType.getName()
+						+ "' using '" + jtd.getClass().getName() + "' to unwrap"
 		);
 	}
 
 	protected static <T extends JavaType<?>> HibernateException unknownWrap(Class<?> valueType, Class<?> sourceType, T jtd) {
 		throw new HibernateException(
-				"Unknown wrap conversion requested: " + valueType.getName() + " to " + sourceType.getName() + " : `" + jtd.getClass().getName() + "` (" + jtd.getJavaTypeClass().getName() + ")"
+				"Could not convert '" + valueType.getName()
+						+ "' to '" + sourceType.getName()
+						+ "' using '" + jtd.getClass().getName() + "' to wrap"
 		);
 	}
 

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/LongJavaType.java

@@ -154,7 +154,7 @@ public <X> Long coerce(X value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Long",
+						"Cannot coerce value '%s' [%s] to Long",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/ShortJavaType.java

@@ -177,7 +177,7 @@ public Short coerce(Object value, CoercionContext coercionContext) {
 		throw new CoercionException(
 				String.format(
 						Locale.ROOT,
-						"Cannot coerce value `%s` [%s] as Short",
+						"Cannot coerce value '%s' [%s] to Short",
 						value,
 						value.getClass().getName()
 				)

hibernate-core/src/main/java/org/hibernate/type/descriptor/java/StringJavaType.java

@@ -79,6 +79,14 @@ public <X> X unwrap(String value, Class<X> type, WrapperOptions options) {
 		if ( Clob.class.isAssignableFrom( type ) ) {
 			return (X) options.getLobCreator().createClob( value );
 		}
+		if ( Integer.class.isAssignableFrom( type ) ) {
+			Integer parsed = Integer.parseInt( value );
+			return (X) parsed;
+		}
+		if ( Long.class.isAssignableFrom( type ) ) {
+			Long parsed = Long.parseLong( value );
+			return (X) parsed;
+		}
 
 		throw unknownUnwrap( type );
 	}
@@ -99,6 +107,12 @@ public <X> String wrap(X value, WrapperOptions options) {
 		if (value instanceof Clob) {
 			return DataHelper.extractString( (Clob) value );
 		}
+		if (value instanceof Integer) {
+			return value.toString();
+		}
+		if (value instanceof Long) {
+			return value.toString();
+		}
 
 		throw unknownWrap( value.getClass() );
 	}