How to resolve "File Upload Failure" when importing a schema with dependany in WSO2 GREG

Schema is one of the main asset model used in WSO2 GREG and you can find more information on https://docs.wso2.com/display/Governance520/Adding+a+Schema.

There can be situations where you want to import a schema to GREG which imports another schema (It has a dependency). 

1. Lets say you have a schema file.
example: original.xsd

 <?xml version="1.0" encoding="UTF-8"?>  
 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:listing1">  
   <xsd:complexType name="Phone1">  
     <xsd:sequence>  
       <xsd:element name="areaCode1" type="xsd:int"/>  
       <xsd:element name="exchange1" type="xsd:int"/>  
       <xsd:element name="number1" type="xsd:int"/>  
     </xsd:sequence>  
   </xsd:complexType>  
 </xsd:schema>

2. Import above schema on publisher as per the instructions given on https://docs.wso2.com/display/Governance520/Adding+a+Schema.

3. Now, you need to import another schema which import/ has reference to previous schema
example: link.xsd

<?xml version="1.0" encoding="UTF-8"?>  
 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:listing">  
   <xsd:import namespace="urn:listing1"  
         schemaLocation="original.xsd"/>  
   <xsd:complexType name="Phone">  
     <xsd:sequence>  
       <xsd:element name="areaCode" type="xsd:int"/>  
       <xsd:element name="exchange" type="xsd:int"/>  
       <xsd:element name="number" type="xsd:int"/>  
     </xsd:sequence>  
   </xsd:complexType>  
 </xsd:schema>  

Issue: You may encounter an error similar to following:

ERROR {org.wso2.carbon.registry.extensions.handlers.utils.SchemaProcessor} - Could not read the XML Schema Definition file. this.schema.needs  
 org.apache.ws.commons.schema.XmlSchemaException: Could not evaluate Schema Definition. This Schema contains Schema Includes that were not resolved  
      at org.apache.ws.commons.schema.SchemaBuilder.handleInclude(SchemaBuilder.java:1676)  
      at org.apache.ws.commons.schema.SchemaBuilder.handleXmlSchemaElement(SchemaBuilder.java:221)  
      at org.apache.ws.commons.schema.SchemaBuilder.build(SchemaBuilder.java:121)  
      at org.apache.ws.commons.schema.XmlSchemaCollection.read(XmlSchemaCollection.java:512)  
      at org.apache.ws.commons.schema.XmlSchemaCollection.read(XmlSchemaCollection.java:385)  
      at org.apache.ws.commons.schema.XmlSchemaCollection.read(XmlSchemaCollection.java:425)  
 ....................  
 Caused by: org.wso2.carbon.registry.core.exceptions.RegistryException: Could not read the XML Schema Definition file. this.schema.needs  
      at org.wso2.carbon.registry.extensions.handlers.utils.SchemaProcessor.putSchemaToRegistry(SchemaProcessor.java:137)  
      at org.wso2.carbon.registry.extensions.handlers.XSDMediaTypeHandler.processSchemaUpload(XSDMediaTypeHandler.java:263)  
      at org.wso2.carbon.registry.extensions.handlers.XSDMediaTypeHandler.put(XSDMediaTypeHandler.java:186)  
      at org.wso2.carbon.registry.core.jdbc.handlers.HandlerManager.put(HandlerManager.java:2503)  
      at org.wso2.carbon.registry.core.jdbc.handlers.HandlerLifecycleManager.put(HandlerLifecycleManager.java:957)  
      at org.wso2.carbon.registry.core.jdbc.EmbeddedRegistry.put(EmbeddedRegistry.java:697)  
      at org.wso2.carbon.registry.core.caching.CacheBackedRegistry.put(CacheBackedRegistry.java:550)  
      at org.wso2.carbon.registry.core.session.UserRegistry.putInternal(UserRegistry.java:827)  
      at org.wso2.carbon.registry.core.session.UserRegistry.access$1000(UserRegistry.java:60)  
      at org.wso2.carbon.registry.core.session.UserRegistry$11.run(UserRegistry.java:803)  
      at org.wso2.carbon.registry.core.session.UserRegistry$11.run(UserRegistry.java:800)  
      at java.security.AccessController.doPrivileged(Native Method)  
      at org.wso2.carbon.registry.core.session.UserRegistry.put(UserRegistry.java:800)  
      at org.wso2.carbon.registry.resource.services.utils.AddResourceUtil.addResource(AddResourceUtil.java:88)  

Solution 1:
Zip all schemas together and upload

Solution 2:
Specify the absolute path for dependent schema file:
example:

 <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="urn:listing">  
   <xsd:import namespace="urn:listing1"  
         schemaLocation="http://www.example.com/schema/original.xsd"/>