org.hibernate.tool.schema.spi.CommandAcceptanceException: Unable to execute command [
    create table Product (
        id int4 not null,
        name varchar(255),
        warranty nvarchar(255),
        primary key (id)
    )]
	at org.hibernate.tool.schema.internal.exec.GenerationTargetToDatabase.accept(GenerationTargetToDatabase.java:63)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlString(SchemaCreatorImpl.java:434)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.applySqlStrings(SchemaCreatorImpl.java:419)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.createFromMetadata(SchemaCreatorImpl.java:310)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.performCreation(SchemaCreatorImpl.java:165)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:134)
	at org.hibernate.tool.schema.internal.SchemaCreatorImpl.doCreation(SchemaCreatorImpl.java:120)
	at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.performDatabaseAction(SchemaManagementToolCoordinator.java:148)
	at org.hibernate.tool.schema.spi.SchemaManagementToolCoordinator.process(SchemaManagementToolCoordinator.java:64)
	at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:458)
	at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:465)
	at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:881)
	at org.hibernate.jpa.test.BaseEntityManagerFunctionalTestCase.buildEntityManagerFactory(BaseEntityManagerFunctionalTestCase.java:79)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:24)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
	at org.junit.internal.runners.statements.FailOnTimeout$StatementThread.run(FailOnTimeout.java:74)
Caused by: org.postgresql.util.PSQLException: ERROR: type "nvarchar" does not exist

Caused by: java.sql.SQLFeatureNotSupportedException: Method org.postgresql.jdbc4.Jdbc4PreparedStatement.setNString(int, String) is not yet implemented.
	at org.postgresql.Driver.notImplemented(Driver.java:670)
	at org.postgresql.jdbc4.AbstractJdbc4Statement.setNString(AbstractJdbc4Statement.java:101)
	at org.hibernate.type.descriptor.sql.NVarcharTypeDescriptor$1.doBind(NVarcharTypeDescriptor.java:46)