# October AP CSA Insider: AP CSA deadlines, webinars, and more!
Published: 2026-10-20
Category: Newsletter
Category URL: https://codehs.com/blog/category/newsletter
Tags: Course Insider, AP CSA
Tag URLs: Course Insider (https://codehs.com/blog/tag/course-insider), AP CSA (https://codehs.com/blog/tag/ap-csa)
URL: https://codehs.com/blog/october-ap-csa-insider-ap-csa-deadlines-webinars-and-more

## **String Method Tips and Common Mistakes**

String methods come up throughout AP CSA, and Part B of the first free-response question on the AP Exam requires students to use them. They can be tricky, since small details are easy to mix up. A few mistakes show up often:

- The second number in **substring(from, to)** is where the substring stops, and that character isn’t included. **"costume".substring(1, 4)** returns **"ost"**. To get a single character as a String, students can use **substring(index, index + 1)**.

- Strings can’t be changed after they’re created. Calling **word.substring(2)**; on its own line does nothing useful, because the result has to be stored, as in **word = word.substring(2);**.

- **indexOf** returns **-1** when it doesn’t find a match, so students should check for that before using the result as an index. Valid indexes run from **0** to **length() - 1**, and anything outside that range causes a **StringIndexOutOfBoundsException**.

- To compare the text in two Strings, students should use **equals**. The **==** operator checks whether two variables refer to the same object, so it can return false even when the text matches.


![image.png](https://prod.superblogcdn.com/site_cuid_cm264m3an0084qegvyd7aetst/images/image-1793113138841-compressed.png)

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## **AP CSA Question of the Day**

As you're preparing for your next lesson, don’t forget to check out the [CodeHS AP CSA Question of the Day (QOTD)](https://codehs.intercom-mail.com/via/e?ob=XRGwnD1SB2VuEaiNXmJXkt8T877TexN7ZoaA7SDBTic%3D&h=eeaeed2328f682737eee9dda2be2498e90b38bac-x13jbr4h_preview104467397)!

CodeHS releases a new multiple-choice question each day that aligns with where you and your students should be in the AP CSA course.

Subscribe to get a daily reminder and answer the question correctly to keep your streak alive!

Answer Today’s Question

_Teaching other courses? Check out the Question of the Day for_ [_AP CSP_](https://codehs.intercom-mail.com/via/e?ob=gC4B0iiV1z47bAKG%2FgN4t3PjYSuGj3abdNP4QITMVs4%3D&h=db4cc9bc81d864b493c968a6c87fe31826e88dc5-x13jbr4h_preview104467397) _,_ [_Python_](https://codehs.intercom-mail.com/via/e?ob=R%2B7DZ2INjFiehNme1P6fnUzqfBwtb00SvvM8qvwObsI%3D&h=79276c92eea4d847b759b1708dc4513d5a19f3db-x13jbr4h_preview104467397) _, and_ [_JavaScript_](https://codehs.intercom-mail.com/via/e?ob=oBxFpUA0YSq%2F98bpJ6FCshKHGezt%2FRkWXmkJqUxzCY8%3D&h=d5039812f1d0f1cb9357aaaaae6cfe652e57a2cb-x13jbr4h_preview104467397) _!_

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## **AP CSA Project of the Month**

This month's featured project is [The Monty Hall Simulator](https://codehs.intercom-mail.com/via/e?ob=mZut7oNpkz8Uy%2FcB29bO2%2F5OQkP%2B50gTl%2Bjjax47iDBI4RxY8DZr0C1%2B6waz5Ahe5f6Z9pPjDB8Q3rr4IdeUCK9Szgnit66EwaUBnjStZGY%3D&h=eb2d55bef4db88476697fa118096f09890e682ca-x13jbr4h_preview104467397). In this project, students will recreate the classic paradox from Let's Make A Deal. They start off recreating the final pick-a-door option and then extend this with a simulator to simulate thousands of iterations as they examine this mathematical puzzle. Students will use loops and conditional statements to help solve this problem. This project should take students about 3 hours and includes autograders.

Assign The Monty Hall Simulator to Students

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## **College Board Student Registration Deadline**

Just a quick reminder that the College Board’s deadline for full-year AP exam orders is November 13th. Exams ordered after that date have a $40 late fee. Many schools set an earlier deadline so their AP coordinator has time to submit orders, so encourage students to check with their coordinator and register soon!

Learn More

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## **Free PD for AP CSA Teachers**

Missed September’s AP CSA Professional Learning Community? The recording is ready to watch whenever it fits your schedule.

AP CSA Professional Learning Community (PLC) - [**Watch Now**](https://codehs.intercom-mail.com/via/e?ob=z2a7G8FG24dl95RCyg0Vx6O0zbIpuOxMg7Xg5ShF3JxEgQhLJCoW%2Fe8Uuwd%2BG9QLaH9yH5x7axJIOM2u2OlW47pop9H4xD7h4sPpp3GtfHOtF5s6IRFG3t%2BldGo%2FDzz0&h=8a4c41fd47bed7df94345e2ea87079a24c3fc5fa-x13jbr4h_preview104467397)

View All Free PD Events

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## **Request a Visit From CodeHS for CSEdWeek**

From **November 30th – December 11th**, CodeHS team members are visiting classrooms to celebrate Computer Science Education Week! Request a visit from the team or explore [Hour of Code](https://codehs.intercom-mail.com/via/e?ob=2XrnP2LR%2F1coKXc6V9nfe%2BuAslA9eOX%2BJFuw15y1JU8%3D&h=3a1f879ab6c1ccb6705fb7115da5e54cf0131661-x13jbr4h_preview104467397) and [Hour of AI](https://codehs.intercom-mail.com/via/e?ob=cYokp6j58YBiish%2FlsuwRwJdJ6DUDVZYfETXDn9HSPc%3D&h=5c7d05b3b5d0b12aa05a62883b4c9ab35c43ddad-x13jbr4h_preview104467397) activities you can assign to students during CSEdWeek.

Request a Visit

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## **Important Platform Updates**

[**Sep 15 · Java IDE**](https://codehs.intercom-mail.com/via/e?ob=7kFkXEbQ9lVHp6WDUy1FEqcdvDE0dBw8VupJ2kgvU4TanLWbwt2B1AHwVqgzPZOk45FqM2ROFgUoB209ppOafLEeZwtNEd8ZlG2Eo%2F%2BNMZQ%3D&h=7ea547be057c4868f752900c3ca7a026d8203105-x13jbr4h_preview104467397)

**Help Students Debug Java One Step at a Time**

Clear Step Over and Step Into controls, responsive breakpoints, and helpful status messages make Java debugging easier for students to learn and use.

[**Aug 26 · Java IDE**](https://codehs.intercom-mail.com/via/e?ob=Ksxt3FxYMwKiv9Z%2FhEelZ2Fezpihy5QzxvSLPBWTsBjX97EvL6jqFqnsP8z%2FT8V40OnOlyljPoATK990fGbRRw%3D%3D&h=ccc9404270fe6ce86c8d74c64b9a71792077c59a-x13jbr4h_preview104467397)

**Faster Java Running**

Improvements to how Java compiles and runs mean your students’ programs start much faster.

See What's New

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## Get More Out of AP CSA With CodeHS Pro

Track progress live, group students for review, and grade Java faster with Pro tools built for your classroom.

Upgrade to Pro

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## **Get Involved & Stay Connected**

- **Join our** [**CodeHS AP CSA Educators Facebook Group**](https://codehs.intercom-mail.com/via/e?ob=u1sEreYszHAM124AMOp8vzbvYxh%2B%2BFOiHGq19HcHAHhpRSRQfwJGj2uuGa%2FKy%2B%2BnwYO%2F9bU0TVJG6iJN2iCgjw%3D%3D&h=c22ccfbfa9ff556dbcaea5ad58b5976edfa39ff2-x13jbr4h_preview104467397)

- **Follow us on** [**X**](https://codehs.intercom-mail.com/via/e?ob=Ar%2FeZnnOJQLrja8UTUCWvyRUFexqSrkbIK63W%2FJ9ZBg%3D&h=cf13c76b25a9688e7d4a0bc2a63593f5e72e7b4e-x13jbr4h_preview104467397) **and** [**Instagram**](https://codehs.intercom-mail.com/via/e?ob=mfFe27EHtl7DQtqXCra%2FanxrLGpI2ferfLDlz3%2FdbJs%3D&h=bc52d22318db23c1548edb9867ed65e67984e1bb-x13jbr4h_preview104467397)

- **Questions? Contact our team at** [**support@codehs.com**](mailto:support@codehs.com) **.**


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