This is my source code.

package com.janki.textgame;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.graphics.g2d.BitmapFont;

public class MyGdxGame extends ApplicationAdapter {
private SpriteBatch batch;
    private BitmapFont font;

    @Override
public void create () {
batch = new SpriteBatch();
        font = new BitmapFont();
        font.setColor(Color.BLUE);
        font.getData().scale(5);
}

    @Override
    public void dispose() {
        batch.dispose();
        font.dispose();
    }

    @Override
public void render () {
Gdx.gl.glClearColor(1, 1, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        batch.begin();
        font.draw(batch,"Hello!",100,400);
batch.end();
}
}


Output gives yellow background but it didn't give any text on the screen.
And there is a warning in event log like this:
22:53:35 Gradle build finished in 15 sec
23:02:13 Throwable: Can't register postfix template. Duplicated key: .field
23:10:34 Gradle build finished with 1 warnings(s) in 47 sec
When I run the app, in logcat it goes on in red font like this:
05-29 13:44:31.632  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.632  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.652  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.652  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.692  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.692  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.692  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.692  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.712  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.712  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.732  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.732  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.742  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.742  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)
05-29 13:44:31.762  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1318>: **** 17563: glUseProgram(3)
05-29 13:44:31.762  17529-17563/com.janki.textgame.android E/Adreno200-ES20? <qgl2DrvAPI_glUseProgram:1304>: **** 17563: glUseProgram(0)