<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!--recycler view to display our data-->
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/idRVCourses"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</RelativeLayout>

public class CourseModal {

    // variables for our course
    // name and description.
    private String courseName;
    private String courseDescription;

    // creating constructor for our variables.
    public CourseModal(String courseName, String courseDescription) {
        this.courseName = courseName;
        this.courseDescription = courseDescription;
    }

    // creating getter and setter methods.
    public String getCourseName() {
        return courseName;
    }

    public void setCourseName(String courseName) {
        this.courseName = courseName;
    }

    public String getCourseDescription() {
        return courseDescription;
    }

    public void setCourseDescription(String courseDescription) {
        this.courseDescription = courseDescription;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="8dp"
    android:elevation="8dp"
    app:cardCornerRadius="8dp">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <!--text view for our course name-->
        <TextView
            android:id="@+id/idTVCourseName"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:text="Course Name"
            android:textColor="@color/black"
            android:textSize="18sp" />

        <!--text view for our course description-->
        <TextView
            android:id="@+id/idTVCourseDescription"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@id/idTVCourseName"
            android:padding="5dp"
            android:text="COurse Description"
            android:textColor="@color/black" />

    </RelativeLayout>

</androidx.cardview.widget.CardView>

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class CourseAdapter extends RecyclerView.Adapter<CourseAdapter.ViewHolder> {

    // creating a variable for array list and context.
    private ArrayList<CourseModal> courseModalArrayList;
    private Context context;

    // creating a constructor for our variables.
    public CourseAdapter(ArrayList<CourseModal> courseModalArrayList, Context context) {
        this.courseModalArrayList = courseModalArrayList;
        this.context = context;
    }

    // method for filtering our recyclerview items.
    public void filterList(ArrayList<CourseModal> filterllist) {
        // below line is to add our filtered
        // list in our course array list.
        courseModalArrayList = filterllist;
        // below line is to notify our adapter 
        // as change in recycler view data.
        notifyDataSetChanged();
    }

    @NonNull
    @Override
    public CourseAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        // below line is to inflate our layout.
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.course_rv_item, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull CourseAdapter.ViewHolder holder, int position) {
        // setting data to our views of recycler view.
        CourseModal modal = courseModalArrayList.get(position);
        holder.courseNameTV.setText(modal.getCourseName());
        holder.courseDescTV.setText(modal.getCourseDescription());
    }

    @Override
    public int getItemCount() {
        // returning the size of array list.
        return courseModalArrayList.size();
    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        // creating variables for our views.
        private TextView courseNameTV, courseDescTV;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            // initializing our views with their ids.
            courseNameTV = itemView.findViewById(R.id.idTVCourseName);
            courseDescTV = itemView.findViewById(R.id.idTVCourseDescription);
        }
    }
}

<?xml version="1.0" encoding="utf-8"?>
<menu 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <!--item for our search view with its id-->
    <item
        android:id="@+id/actionSearch"
        android:icon="@android:drawable/ic_menu_search"
        android:title="Search"
        app:actionViewClass="androidx.appcompat.widget.SearchView"
        app:showAsAction="ifRoom|collapseActionView" />

</menu>

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.SearchView;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

    // creating variables for
    // our ui components.
    private RecyclerView courseRV;

    // variable for our adapter
    // class and array list
    private CourseAdapter adapter;
    private ArrayList<CourseModal> courseModalArrayList;

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

        // initializing our variables.
        courseRV = findViewById(R.id.idRVCourses);

        // calling method to 
        // build recycler view.
        buildRecyclerView();
    }

    // calling on create option menu
    // layout to inflate our menu file.
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // below line is to get our inflater
        MenuInflater inflater = getMenuInflater();

        // inside inflater we are inflating our menu file.
        inflater.inflate(R.menu.search_menu, menu);

        // below line is to get our menu item.
        MenuItem searchItem = menu.findItem(R.id.actionSearch);

        // getting search view of our item.
        SearchView searchView = (SearchView) searchItem.getActionView();

        // below line is to call set on query text listener method.
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String query) {
                return false;
            }

            @Override
            public boolean onQueryTextChange(String newText) {
                // inside on query text change method we are 
                // calling a method to filter our recycler view.
                filter(newText);
                return false;
            }
        });
        return true;
    }

    private void filter(String text) {
        // creating a new array list to filter our data.
        ArrayList<CourseModal> filteredlist = new ArrayList<>();

        // running a for loop to compare elements.
        for (CourseModal item : courseModalArrayList) {
            // checking if the entered string matched with any item of our recycler view.
            if (item.getCourseName().toLowerCase().contains(text.toLowerCase())) {
                // if the item is matched we are
                // adding it to our filtered list.
                filteredlist.add(item);
            }
        }
        if (filteredlist.isEmpty()) {
            // if no item is added in filtered list we are 
            // displaying a toast message as no data found.
            Toast.makeText(this, "No Data Found..", Toast.LENGTH_SHORT).show();
        } else {
            // at last we are passing that filtered
            // list to our adapter class.
            adapter.filterList(filteredlist);
        }
    }

    private void buildRecyclerView() {

        // below line we are creating a new array list
        courseModalArrayList = new ArrayList<>();

        // below line is to add data to our array list.
        courseModalArrayList.add(new CourseModal("DSA", "DSA Self Paced Course"));
        courseModalArrayList.add(new CourseModal("JAVA", "JAVA Self Paced Course"));
        courseModalArrayList.add(new CourseModal("C++", "C++ Self Paced Course"));
        courseModalArrayList.add(new CourseModal("Python", "Python Self Paced Course"));
        courseModalArrayList.add(new CourseModal("Fork CPP", "Fork CPP Self Paced Course"));

        // initializing our adapter class.
        adapter = new CourseAdapter(courseModalArrayList, MainActivity.this);

        // adding layout manager to our recycler view.
        LinearLayoutManager manager = new LinearLayoutManager(this);
        courseRV.setHasFixedSize(true);

        // setting layout manager 
        // to our recycler view.
        courseRV.setLayoutManager(manager);

        // setting adapter to 
        // our recycler view.
        courseRV.setAdapter(adapter);
    }
}