HashMap is one of the most frequently asked topics in Java interviews — it effectively tests a candidate’s understanding of data structures and engineering trade-offs. This article breaks down its core design and implementation details. ...
The box-shadow property in CSS3 is highly versatile. When used creatively, it can produce rich visual effects with pure CSS. Here are several practical techniques. ...
While working on an image upload feature, I encountered a runtime exception on certain devices: 1 2 3 4 5 6 7 8 9 java.io.FileNotFoundException: /mnt/sdcard/Android/data/com.xxxxxx.android/files/xxxx open failed: EBUSY (Device or resource busy) at libcore.io.IoBridge.open(IoBridge.java:406) at java.io.FileOutputStream.<init>(FileOutputStream.java:88) ... Caused by: libcore.io.ErrnoException: open failed: EBUSY (Device or resource busy) at libcore.io.Posix.open(Native Method) at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110) ... ...
I came across stormzhang’s Tencent interview questions and decided to work through them, documenting my answers and thought process. Topics covered: Android fundamentals (processes, Activities, Handler) Screen density and resource qualifiers Thread synchronization in Java System design (resumable downloads, network architecture) ...
What is a Lambda Expression? Lambda expressions are a core feature introduced in Java 8, enabling more concise code. Here is the most straightforward example: 1 2 3 4 5 6 7 8 9 10 Runnable runnable1 = new Runnable() { @Override public void run() { System.out.println("runnable1 start!!!"); } }; Runnable runnable2 = () -> System.out.println("runnable2 start!!!"); runnable1.run(); runnable2.run(); Both blocks are equivalent, but the lambda version is a single line. The basic form is () -> expression or () -> { statements; }. ...
Ever since getting a Nexus device, I never wanted to plug in a USB cable again. Android supports ADB debugging over WiFi, making cable-free development a reality. ...
SQLite is a lightweight relational database engine built into Android, ideal for local data persistence. The android.database.sqlite package provides everything you need without additional setup. ...
The Palette library, part of Android Support Library (now migrated to AndroidX palette), extracts representative colors from a Bitmap. In Material Design, deriving UI colors from imagery is a common pattern, and Palette makes this straightforward. ...
Parallax scrolling is a common UI effect where different layers move at different speeds during scrolling, creating a sense of depth. ...
RecyclerView is a more flexible replacement for ListView. According to the official documentation, it efficiently maintains a limited collection of scrolling data items, and is recommended when your Views need to interact with user gestures and network data. ...