Basic Implementation of Realm for Android

AndroidToolbox-Realm.java

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import io.realm.Realm;
import io.realm.RealmResults;

public class MainActivity extends AppCompatActivity {

    // Class specific variables and constants
    public static String TAG = "MainActivity";

    // Helper Variables
    private Realm mRealm;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Set Helper Variables
        Realm.init(this);
        mRealm = Realm.getDefaultInstance();

        // Should not be done in onCreate, but this is just a demonstration
        performRealmTransactions(mRealm);
    }

    public void performRealmTransactions(Realm realm) {
        Log.d(TAG, "Creating Mike Campbell");
        realmCreate(realm, new Person("Mike", "Campbell"));

        Log.d(TAG, "Creating Jim Smith");
        realmCreate(realm, new Person("Jim", "Smith"));

        Log.d(TAG, "Updating Mike Campbell to Michael Campbell");
        realmUpdatePerson(realm, "Mike", "Michael");

        Log.d(TAG, "Displaying all Persons");
        realmLogAllPersons(realm);

        Log.d(TAG, "Deleting all Jim's");
        realmDeleteAllPersonsByFirstName(realm, "Jim");

        Log.d(TAG, "Displaying all Persons");
        realmLogAllPersons(realm);

        Log.d(TAG, "Deleting all Persons");
        realmDeleteAllPersons(realm);

        Log.d(TAG, "Displaying all Persons");
        realmLogAllPersons(realm);
    }

    public void realmLogAllPersons(Realm realm) {
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                RealmResults<Person> results = realm.where(Person.class).findAll();
                for (Person p : results) {
                    Log.d(TAG + ":FindAll", p.toString());
                }
            }
        });
    }

    public void realmCreate(Realm realm, final Person p) {

        realm.executeTransaction(new Realm.Transaction() {

            @Override
            public void execute(Realm realm) {
                Person realmPerson = realm.createObject(Person.class);
                realmPerson.setFirstName(p.getFirstName());
                realmPerson.setLastName(p.getLastName());
            }
        });
    }

    public Person realmFindPersonByFirstName(Realm realm, String firstName) {
        final Person person = realm.where(Person.class)
                                   .equalTo("firstName", firstName)
                                   .findFirst();
        Log.d(TAG + ":Find", person.toString());

        return person;
    }

    public void realmUpdatePerson(Realm realm, String currentFirstName, final String newFirstName) {
        final Person person = realmFindPersonByFirstName(realm, currentFirstName);

        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                person.setFirstName(newFirstName);
            }
        });


        Log.d(TAG, "Updated Person: " + currentFirstName + " -> " + newFirstName);
        Log.d(TAG, realmFindPersonByFirstName(realm, "Michael").toString());
    }

    public void realmDeleteAllPersons(Realm realm) {
        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {
                realm.delete(Person.class);
            }
        });

    }

    public void realmDeleteAllPersonsByFirstName(Realm realm, final String firstName) {

        final RealmResults<Person> result = realm.where(Person.class)
                .equalTo("firstName", firstName)
                .findAll();

        realm.executeTransaction(new Realm.Transaction() {
            @Override
            public void execute(Realm realm) {

                result.deleteAllFromRealm();
            }
        });

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.i(TAG, "Activity destroyed.");
        mRealm.close();
    }
}

Person.java

package com.plugtech.realmtoolbox;

import io.realm.RealmObject;

/** PERSON CLASS.  FOR DEMONSTRATIVE PURPOSES ONLY.  **/
public class Person  extends RealmObject {
    private String firstName;
    private String lastName;

    public Person() { /* required default constructor */}

    public Person(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return "Person: " + getFirstName() + " " + getLastName();
    }
}