XSD validation for dummies

I have an XML file I got from a customer that our system has a problem processing. They have a history of sending in invalid files so I want to start validating each file before we start debugging and stuffI got an XSD file, which imports 3 more XSD files:

Main file:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:sw3="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.02" xmlns:sw2="urn:iso:std:iso:20022:tech:xsd:pacs.002.001.03" xmlns:sw6="urn:iso:std:iso:20022:tech:xsd:camt.056.001.01" xmlns:S2SDDDnf="urn:S2SDDDnf:xsd:$MPEDDDnfBlkDirDeb" targetNamespace="urn:S2SDDDnf:xsd:$MPEDDDnfBlkDirDeb" elementFormDefault="qualified">
	<xs:import namespace="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.02" schemaLocation="pacs.003.001.02.xsd"/>
	<xs:import namespace="urn:iso:std:iso:20022:tech:xsd:pacs.002.001.03" schemaLocation="pacs.002.001.03.xsd"/>
	<xs:import namespace="urn:iso:std:iso:20022:tech:xsd:camt.056.001.01" schemaLocation="camt.056.001.01.xsd"/>
	<xs:element name="MPEDDDnfBlkDirDeb">

One of the imported files:

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.02" targetNamespace="urn:iso:std:iso:20022:tech:xsd:pacs.003.001.02" elementFormDefault="qualified">
	<xs:element name="Document" type="Document"/>
	<!-- STEP2 SDD Schema, new name FIToFICstmrDrctDbt, 2010-01-27 -->
	<xs:complexType name="Document">
			<xs:element name="FIToFICstmrDrctDbt" type="FIToFICustomerDirectDebitV02"/>

I need some tool where I can open the xml, define these XSDs and validate the xml. Its gotta be free cause I’m not getting any budget for this.
The ‘dummies’ in the title means I need a very clear explanation :)

Eclipse can do it.

JDeveloper can do it too, but who uses that?

(I should revisit this topic next year, when I’ll be finally neck-deep in XML/schema/xquery. Yuck.)

I know you said it had to be free, but XMLSpy is the best tool I’ve used for that. Last time I looked around for free and/or open source tools, I was underwhelmed and asked my boss to re-up my license (thankfully he did). Would love to find a good open source tool.

Well we’re out of XMLSpy licenses and not about to get new ones. But eclipse does do the job so yay for free.