Using Exception Methods

All exceptions support built-in methods for returning the error message and exception type. In addition to the standard exception class, there are several different types of exceptions:

Exception	Description
`AsyncException`	Any problem with an asynchronous operation, such as failing to enqueue an asynchronous call.
`CalloutException`	Any problem with a Web service operation, such as failing to make a callout to an external system.
`DmlException`	Any problem with a DML statement, such as an `insert` statement missing a required field on a record.
`EmailException`	Any problem with email, such as failure to deliver. For more information, see Apex Email Classes.
`InvalidParameterValueException`	Any problem with a URL. This is generally used with Visualforce pages. For more information on Visualforce, see the Visualforce Developer's Guide.
`JSONException`	Any problem with JSON serialization and deserialization operations. For more information, see the methods of `System.JSON`, `System.JSONParser`, and `System.JSONGenerator`.
`ListException`	Any problem with a list, such as attempting to access an index that is out of bounds.
`MathException`	Any problem with a mathematical operation, such as dividing by zero.
`NoAccessException`	Any problem with unauthorized access, such as trying to access an sObject that the current user does not have access to. This is generally used with Visualforce pages. For more information on Visualforce, see the Visualforce Developer's Guide.
`NoDataFoundException`	Any problem with data that does not exist, such as trying to access an sObject that has been deleted. This is generally used with Visualforce pages. For more information on Visualforce, see the Visualforce Developer's Guide.
`NoSuchElementException`	Used specifically by the Iterator`next` method. This exception is thrown if you try to access items beyond the end of the list. For example, if `iterator.hasNext() == false` and you call `iterator.next()`, this exception is thrown.
`NullPointerException`	Any problem with dereferencing null, such as in the following code: String s; s.toLowerCase(); // Since s is null, this call causes // a NullPointerException
`QueryException`	Any problem with SOQL queries, such as assigning a query that returns no records or more than one record to a singleton sObject variable.
`RequiredFeatureMissing`	A Chatter feature is required for code that has been deployed to an organization that does not have Chatter enabled.
`SearchException`	Any problem with SOSL queries executed with SOAP API`search()` call, for example, when the `searchString` parameter contains less than two characters. For more information, see the SOAP API Developer's Guide.
`SecurityException`	Any problem with static methods in the Crypto utility class. For more information, see `Crypto` Class.
`SerializationException`	Any problem with the serialization of data. This is generally used with Visualforce pages. For more information on Visualforce, see the Visualforce Developer's Guide.
`SObjectException`	Any problem with sObject records, such as attempting to change a field in an `update` statement that can only be changed during `insert`.
`StringException`	Any problem with Strings, such as a String that is exceeding your heap size.
`TypeException`	Any problem with type conversions, such as attempting to convert the String 'a' to an Integer using the `valueOf` method.
`VisualforceException`	Any problem with a Visualforce page. For more information on Visualforce, see the Visualforce Developer's Guide.
`XmlException`	Any problem with the XmlStream classes, such as failing to read or write XML. For more information, see XmlStream Classes.

The following is an example using the DmlException exception:

Account[] accts = new Account[]{new Account(billingcity = 'San Jose')};
try {
    insert accts;
} catch (System.DmlException e) {
    for (Integer i = 0; i < e.getNumDml(); i++) {
        // Process exception here
        System.debug(e.getDmlMessage(i)); 
    }
}

Common Exception Methods

Exception methods are all called by and operate on a particular instance of an exception. The table below describes all instance exception methods. All types of exceptions have the following methods in common:

Name	Arguments	Return Type	Description
`getCause`		Exception	Returns the cause of the exception as an exception object.
`getLineNumber`		Integer	Returns the line number from where the exception was thrown.
`getMessage`		String	Returns the error message that displays for the user.
`getStackTraceString`		String	Returns the stack trace as a string.
`getTypeName`		String	Returns the type of exception, such as DmlException, ListException, MathException, and so on.
`initCause`	Exception `cause`	Void	Sets the cause for this exception, if one has not already been set.
`setMessage`	String `s`	Void	Sets the error message that displays for the user.

DMLException and EmailException Methods

In addition to the common exception methods, DMLExceptions and EmailExceptions have the following additional methods:

Name	Arguments	Return Type	Description
`getDmlFieldNames`	Integer `i`	String []	Returns the names of the field or fields that caused the error described by the `i`th failed row.
`getDmlFields`	Integer `i`	Schema.sObjectField []	Returns the field token or tokens for the field or fields that caused the error described by the `i`th failed row. For more information on field tokens, see Dynamic Apex.
`getDmlId`	Integer `i`	String	Returns the ID of the failed record that caused the error described by the `i`th failed row.
`getDmlIndex`	Integer `i`	Integer	Returns the original row position of the `i`th failed row.
`getDmlMessage`	Integer `i`	String	Returns the user message for the `i`th failed row.
`getDmlStatusCode`	Integer `i`	String	Deprecated. Use getDmlType instead. Returns the Apex failure code for the `i`th failed row.
`getDmlType`	Integer `i`	System.StatusCode	Returns the value of the System.StatusCode enum. For example: try { insert new Account(); } catch (System.DmlException ex) { System.assertEquals( StatusCode.REQUIRED_FIELD_MISSING, ex.getDmlType(0)); } For more information about System.StatusCode, see Enums.
`getNumDml`		Integer	Returns the number of failed rows for DML exceptions.