Not able to fetch data from API using Retrofit

I want to fatch data from restcountries api. MainActivity

 public class MainActivity extends AppCompatActivity {
    TextView tv4,tv1,tv2,tv3;
    EditText edit;
        public void loadCountryInfo(View view) {
            //EditText cn=(EditText) findViewById(R.id.CountryName);
            edit=(EditText)findViewById(R.id.ed1);
            final String countryName=edit.getText().toString();
            final String strURL="http://restcountries.eu";

            if (countryName.length() == 0) {
                Toast.makeText(this, "No Country Specified", Toast.LENGTH_SHORT).show();
            } else {
                Retrofit retrofit = new Retrofit.Builder()
                        .baseUrl(strURL)
                        .addConverterFactory(GsonConverterFactory.create())
                        .build();

                RetrofiApi service = retrofit.create(RetrofiApi.class);

                Call<CountriesInfo> call = service.getCountryInfo(countryName);//countryName

                call.enqueue(new Callback<CountriesInfo>() {
                    @Override
                    public void onResponse(Call<CountriesInfo> call, Response<CountriesInfo> response) {

                        tv4=(TextView) findViewById(R.id.textView4);
                        tv1=(TextView) findViewById(R.id.textView1);
                        tv2=(TextView) findViewById(R.id.textView2);
                        tv3=(TextView) findViewById(R.id.textView3);
                        try {

                            tv1.setText(response.body().getCapital());    
                            tv2.setText(response.body().getArea().toString());                              
 tv3.setText(response.body().getPopulation().toString());
                             tv4.setText(response.body().getName().toString());

                        } catch (Exception e) {
                            tv1.setText(countryName);
                            Toast.makeText(MainActivity.this, "Something Went Wrong! Maybe due to invalid country name or Something like this.", Toast.LENGTH_SHORT).show();
                            int code =response.code();

                            System.out.println("this is errror♠♠  "+code);
                            e.printStackTrace();
                        }
                    }

                    @Override
                    public void onFailure(Call<CountriesInfo> call, Throwable t) {
                        //System.out.println("Here is some this is errror♠♠  ");
                        String code =  t.getMessage();
                        System.out.println("this is errror♠♠ helloooooooooo "+code);
                        Toast.makeText(MainActivity.this, "Something Went Wrong! Maybe due to invalid country name.", Toast.LENGTH_SHORT).show();
                    }
                });

            }
        }
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            Button b=(Button) findViewById(R.id.button);
            //loadCountryInfo();
           }

    }

CountriesInfo: getters and setter


public class CountriesInfo {

    @SerializedName("name")
    @Expose
    private String name;
    @SerializedName("capital")
    @Expose
    private String capital;
    @SerializedName("altSpellings")
    @Expose
    private List<String> altSpellings = new ArrayList<String>();
    @SerializedName("relevance")
    @Expose
    private String relevance;
    @SerializedName("region")
    @Expose
    private String region;
    @SerializedName("subregion")
    @Expose
    private String subregion;
//    @SerializedName("translations")
//    @Expose
//    private Translations translations;
    @SerializedName("population")
    @Expose
    private Integer population;
    @SerializedName("latlng")
    @Expose
    private List<Double> latlng = new ArrayList<Double>();
    @SerializedName("demonym")
    @Expose
    private String demonym;
    @SerializedName("area")
    @Expose
    private Double area;
    @SerializedName("gini")
    @Expose
    private Double gini;
    @SerializedName("timezones")
    @Expose
    private List<String> timezones = new ArrayList<String>();
    @SerializedName("borders")
    @Expose
    private List<String> borders = new ArrayList<String>();
    @SerializedName("nativeName")
    @Expose
    private String nativeName;
    @SerializedName("callingCodes")
    @Expose
    private List<String> callingCodes = new ArrayList<String>();
    @SerializedName("topLevelDomain")
    @Expose
    private List<String> topLevelDomain = new ArrayList<String>();
    @SerializedName("alpha2Code")
    @Expose
    private String alpha2Code;
    @SerializedName("alpha3Code")
    @Expose
    private String alpha3Code;
    @SerializedName("currencies")
    @Expose
    private List<String> currencies = new ArrayList<String>();
    @SerializedName("languages")
    @Expose
    private List<String> languages = new ArrayList<String>();

    /**
     *
     * @return
     *     The name
     */
    public String getName() {
        return name;
    }

    /**
     *
     * @param name
     *     The name
     */
    public void setName(String name) {
        this.name = name;
    }

    /**
     *
     * @return
     *     The capital
     */
    public String getCapital() {
        return capital;
    }

    /**
     *
     * @param capital
     *     The capital
     */
    public void setCapital(String capital) {
        this.capital = capital;
    }

    /**
     *
     * @return
     *     The altSpellings
     */
    public List<String> getAltSpellings() {
        return altSpellings;
    }

    /**
     *
     * @param altSpellings
     *     The altSpellings
     */
    public void setAltSpellings(List<String> altSpellings) {
        this.altSpellings = altSpellings;
    }

    /**
     *
     * @return
     *     The relevance
     */
    public String getRelevance() {
        return relevance;
    }

    /**
     *
     * @param relevance
     *     The relevance
     */
    public void setRelevance(String relevance) {
        this.relevance = relevance;
    }

    /**
     *
     * @return
     *     The region
     */
    public String getRegion() {
        return region;
    }

    /**
     *
     * @param region
     *     The region
     */
    public void setRegion(String region) {
        this.region = region;
    }

    /**
     *
     * @return
     *     The subregion
     */
    public String getSubregion() {
        return subregion;
    }

    /**
     *
     * @param subregion
     *     The subregion
     */
    public void setSubregion(String subregion) {
        this.subregion = subregion;
    }

    /**
     *
     * @return
     *     The translations
     */
//    public Translations getTranslations() {
//        return translations;
//    }

    /**
     *
     * @param translations
     *     The translations
     */
//    public void setTranslations(Translations translations) {
//        this.translations = translations;
//    }

    /**
     *
     * @return
     *     The population
     */
    public Integer getPopulation() {
        return population;
    }

    /**
     *
     * @param population
     *     The population
     */
    public void setPopulation(Integer population) {
        this.population = population;
    }

    /**
     *
     * @return
     *     The latlng
     */
    public List<Double> getLatlng() {
        return latlng;
    }

    /**
     *
     * @param latlng
     *     The latlng
     */
    public void setLatlng(List<Double> latlng) {
        this.latlng = latlng;
    }

    /**
     *
     * @return
     *     The demonym
     */
    public String getDemonym() {
        return demonym;
    }

    /**
     *
     * @param demonym
     *     The demonym
     */
    public void setDemonym(String demonym) {
        this.demonym = demonym;
    }

    /**
     *
     * @return
     *     The area
     */
    public Double getArea() {
        return area;
    }

    /**
     *
     * @param area
     *     The area
     */
    public void setArea(Double area) {
        this.area = area;
    }

    /**
     *
     * @return
     *     The gini
     */
    public Double getGini() {
        return gini;
    }

    /**
     *
     * @param gini
     *     The gini
     */
    public void setGini(Double gini) {
        this.gini = gini;
    }

    /**
     *
     * @return
     *     The timezones
     */
    public List<String> getTimezones() {
        return timezones;
    }

    /**
     *
     * @param timezones
     *     The timezones
     */
    public void setTimezones(List<String> timezones) {
        this.timezones = timezones;
    }

    /**
     *
     * @return
     *     The borders
     */
    public List<String> getBorders() {
        return borders;
    }

    /**
     *
     * @param borders
     *     The borders
     */
    public void setBorders(List<String> borders) {
        this.borders = borders;
    }

    /**
     *
     * @return
     *     The nativeName
     */
    public String getNativeName() {
        return nativeName;
    }

    /**
     *
     * @param nativeName
     *     The nativeName
     */
    public void setNativeName(String nativeName) {
        this.nativeName = nativeName;
    }

    /**
     *
     * @return
     *     The callingCodes
     */
    public List<String> getCallingCodes() {
        return callingCodes;
    }

    /**
     *
     * @param callingCodes
     *     The callingCodes
     */
    public void setCallingCodes(List<String> callingCodes) {
        this.callingCodes = callingCodes;
    }

    /**
     *
     * @return
     *     The topLevelDomain
     */
    public List<String> getTopLevelDomain() {
        return topLevelDomain;
    }

    /**
     *
     * @param topLevelDomain
     *     The topLevelDomain
     */
    public void setTopLevelDomain(List<String> topLevelDomain) {
        this.topLevelDomain = topLevelDomain;
    }

    /**
     *
     * @return
     *     The alpha2Code
     */
    public String getAlpha2Code() {
        return alpha2Code;
    }

    /**
     *
     * @param alpha2Code
     *     The alpha2Code
     */
    public void setAlpha2Code(String alpha2Code) {
        this.alpha2Code = alpha2Code;
    }

    /**
     *
     * @return
     *     The alpha3Code
     */
    public String getAlpha3Code() {
        return alpha3Code;
    }

    /**
     *
     * @param alpha3Code
     *     The alpha3Code
     */
    public void setAlpha3Code(String alpha3Code) {
        this.alpha3Code = alpha3Code;
    }

    /**
     *
     * @return
     *     The currencies
     */
    public List<String> getCurrencies() {
        return currencies;
    }

    /**
     *
     * @param currencies
     *     The currencies
     */
    public void setCurrencies(List<String> currencies) {
        this.currencies = currencies;
    }

    /**
     *
     * @return
     *     The languages
     */
    public List<String> getLanguages() {
        return languages;
    }

    /**
     *
     * @param languages
     *     The languages
     */
    public void setLanguages(List<String> languages) {
        this.languages = languages;
    }

}

RetrofiApi Interface : HTTP requests


public interface RetrofiApi {
   // String base_url = "https://restcountries.eu/";
    @GET("/rest/v2/name/")
    Call<CountriesInfo> getCountryInfo(@Query("q") String name);
}

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.sony.finalsubmission.MainActivity">

    <EditText
        android:id="@+id/ed1"
        android:layout_width="322dp"
        android:layout_height="87dp"
        android:hint="kombro"
        app:layout_constraintBottom_toTopOf="@+id/button"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:ignore="MissingConstraints" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="322dp"
        android:layout_height="50dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/textView2"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button"
        tools:ignore="MissingConstraints" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="322dp"
        android:layout_height="50dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/textView3"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView1"
        tools:ignore="MissingConstraints" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="322dp"
        android:layout_height="50dp"
        android:text="TextView"
        app:layout_constraintBottom_toTopOf="@+id/textView4"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        tools:ignore="MissingConstraints" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="322dp"
        android:layout_height="50dp"
        android:text="TextView"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView3"
        tools:ignore="MissingConstraints" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintBottom_toTopOf="@+id/textView1"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/ed1"
        android:onClick="loadCountryInfo"/>
</android.support.constraint.ConstraintLayout>

I am getting java.lang.NullPointerException in com.example.sony.finalsubmission.MainActivity$1.onResponse(MainActivity.java:53)

square / retrofit

Not able to fetch data from API using Retrofit #2574