SQL

// make SQL query

QueryManager queryManager = workspace.getQueryManager();

// we want find 'document1'

String sqlStatement = "SELECT * FROM nt:file WHERE jcr:path = '/folder1/folder2/document1'";

// create query

Query query = queryManager.createQuery(sqlStatement, Query.SQL);

// execute query and fetch result

QueryResult result = query.execute();

XPath

// make SQL query

QueryManager queryManager = workspace.getQueryManager();

// we want to find 'document1'

String xpathStatement = "/jcr:root/folder1[1]/folder2[1]/element(document1,nt:file)[1]";

// create query

Query query = queryManager.createQuery(xpathStatement, Query.XPATH);

// execute query and fetch result

QueryResult result = query.execute();

Remark: The indexes [1] are used in order to get the same result as the SQL statement. SQL by default only returns the first node, whereas XPath fetches by default all nodes.