My Updated code

My Content provider:

package com.phehossof.launcher;

import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.HashMap;
import java.util.Objects;

public class ProviderContent extends ContentProvider {
    static final String PROVIDER_NAME ="com.phehossof.launcher.ProviderContent";
    static final String URL = "content://" + PROVIDER_NAME +"/acl";
    static final Uri CONTENT_URI = Uri.parse(URL);
    static final String id = "id";
    static final String name = "name";
    static final String grade = "grade";
    static final String department = "department";
    static final int uriCode = 1;
    static final UriMatcher uriMatcher;

    private static HashMap<String, String> values;
    static {
        uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
        uriMatcher.addURI(PROVIDER_NAME, "acl", uriCode);
        uriMatcher.addURI(PROVIDER_NAME, "acl/*", uriCode);
    }

    @Override
    public boolean onCreate() {
        Context context = getContext();
        DatabaseHelper dbHelper = new DatabaseHelper(context);
        db = dbHelper.getWritableDatabase();
        return db != null;
    }

    @Nullable
    @Override
    public Cursor query(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection, @Nullable String[] selectionArgs, @Nullable String sortOrder) {
        SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
        qb.setTables(TABLE_NAME);
        if (uriMatcher.match(uri) == uriCode) {
            qb.setProjectionMap(values);
        } else {
            throw new IllegalArgumentException("Unknown URI " + uri);
        }
        if (sortOrder == null || Objects.equals(sortOrder, "")) {
            sortOrder = id;
        }
        Cursor c = qb.query(db, projection, selection, selectionArgs, null, null, sortOrder);
        c.setNotificationUri(Objects.requireNonNull(getContext()).getContentResolver(), uri);
        return c;
    }

    @Nullable
    @Override
    public String getType(@NonNull Uri uri) {
        if (uriMatcher.match(uri) == uriCode) {
            return "vnd.android.cursor/acl";
        }
        throw new IllegalArgumentException("Unsupported URI:" + uri);
    }

    @Nullable
    @Override
    public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {
        long rowID = db.insert(TABLE_NAME,"", values);
        if (rowID > 0) {
            Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
            Objects.requireNonNull(getContext()).getContentResolver().notifyChange(_uri, null);
            return _uri;
        }
        throw new SQLiteException("Failed to add record into " + uri);
    }

    @Override
    public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {
        int count;
        if (uriMatcher.match(uri) == uriCode) {
            count = db.delete(TABLE_NAME, selection, selectionArgs);
        } else {
            throw new IllegalArgumentException("Unknown URI " + uri);
        }
        Objects.requireNonNull(getContext()).getContentResolver().notifyChange(uri, null);
        return count;
    }

    @Override
    public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection, @Nullable String[] selectionArgs) {
        int count;
        if (uriMatcher.match(uri) == uriCode) {
            count = db.update(TABLE_NAME, values, selection, selectionArgs);
        } else {
            throw new IllegalArgumentException("Unknown URI " + uri);
        }
        Objects.requireNonNull(getContext()).getContentResolver().notifyChange(uri, null);
        return count;
    }

    private SQLiteDatabase db;
    static final String DATABASE_NAME = "EmpDB";
    static final String TABLE_NAME = "Employees";
    static final int DATABASE_VERSION = 1;
    static final String CREATE_DB_TABLE = " CREATE TABLE " + TABLE_NAME
            + " (id INTEGER PRIMARY KEY AUTOINCREMENT, "
            + " name TEXT NOT NULL);";


    private static class DatabaseHelper extends SQLiteOpenHelper {
        DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
        }

        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL(CREATE_DB_TABLE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
            onCreate(db);
        }
    }
}

My manifest:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.phehossof.launcher">
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:networkSecurityConfig="@xml/network_security_config"
        android:icon="@mipmap/launcher_icon"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/launcher_icon_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="AllowBackup,GoogleAppIndexingWarning">
        <activity
            android:name=".ActivityHome"
            android:label="Phoenix Launcher"
            android:theme="@android:style/Theme.Wallpaper.NoTitleBar.Fullscreen"
            android:launchMode="singleTask"
            android:stateNotNeeded="true" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.HOME" />
                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.phehossof.launcher.ActivityApp"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen" >
        </activity>
        <provider
            android:authorities="com.phehossof.launcher.providercontent"
            android:name=".ProviderContent"
            tools:ignore="ExportedContentProvider">
        </provider>
    </application>
</manifest>