SoapAPISample.java

public String createSample() {
    String result = null;
    try {
        // Create a new sObject of type Contact
        // and fill out its fields.
        SObject contact = new SObject();
        contact.setType("Contact");
        contact.setField("FirstName", "Otto");
        contact.setField("LastName", "Jespersen");
        contact.setField("Salutation", "Professor");
        contact.setField("Phone", "(999) 555-1234");
        contact.setField("Title", "Philologist");
        // Add this sObject to an array
        SObject[] contacts = new SObject[1];
        contacts[0] = contact;
        // Make a create call and pass it the array of sObjects
        SaveResult[] results = partnerConnection.create(contacts);

        // Iterate through the results list
        // and write the ID of the new sObject
        // or the errors if the object creation failed.
        // In this case, we only have one result
        // since we created one contact.
        for (int j = 0; j < results.length; j++) {
            if (results[j].isSuccess()) {
                result = results[j].getId();
                System.out.println(
                    "\nA contact was created with an ID of: " + result
                );
            } else {
                // There were errors during the create call,
                // go through the errors array and write
                // them to the console
                for (int i = 0; i < results[j].getErrors().length; i++) {
                    Error err = results[j].getErrors()[i];
                    System.out.println("Errors were found on item " + j);
                    System.out.println("Error code: " +
                    err.getStatusCode().toString());
                    System.out.println("Error message: " + err.getMessage());
                }
            }
        }
    } catch (ConnectionException ce) {
        ce.printStackTrace();
    }
    return result;
}

http://resources.docs.salesforce.com/198/0/ja-jp/sfdc/pdf/apex_api.pdf