Master IDEA Debugging: Essential Steps and Tips for Java Developers

What Is Debugging and Why It Matters

Debugging is a core skill for programmers that lets you trace code execution, locate runtime exceptions, and track online issues. In many enterprises the ratio of development to debugging effort is roughly 1:1.5, meaning effective debugging is essential for productive development.

View the program’s execution flow.

Understand complex logic that is hard to grasp from static code alone.

Improve problem‑solving ability by locating and fixing issues independently.

Debugging Steps in IntelliJ IDEA

Set a breakpoint (F9).

Start debugging using the toolbar. The toolbar provides eight main actions:

Jump to the line currently being executed.

Step over – move to the next line without entering a method.

Step into – enter a method when the current line calls one.

Force step into – enter any method, including library code.

Step out – exit the current method back to its caller.

Run to cursor – execute code until it reaches the line where the cursor is placed.

Run to cursor (alternative shortcut).

Evaluate expression – modify variable values or compute expressions on the fly.

Observe variables:

View variables in the program editor.

View variables in the Debugger’s Variables pane.

Hover over a variable name to see its current value.

View program output in the standard console.

Jump to the Current Execution Line (Alt + F10)

Press Alt + F10 to switch the editor focus to the line that the debugger is currently executing.

Step Over (F8)

Advances execution line by line without entering called methods, useful for skipping over library code.

Step Into (F7)

Enters the method body of the current line, allowing you to debug custom code while ignoring library implementations.

Force Step Into (Alt + Shift + F7)

Enters any method, including JDK or third‑party library code, which is handy for exploring source implementations.

Step Out (Shift + F8)

Exits the current method and returns to the caller.

Backtrack Breakpoint

Returns execution to the point where the current method was called, allowing you to re‑run a method without restarting the entire debug session.

Run to Cursor (F9)

Executes the program until it reaches the line where the cursor is placed, eliminating the need to set a temporary breakpoint.

Evaluate Expression (Alt + F8)

Opens the Evaluate Expression dialog where you can change variable values or compute arbitrary expressions to test different scenarios during debugging.

Conditional Breakpoints

Right‑click a breakpoint, select “Condition”, and specify an expression; the debugger pauses only when the condition evaluates to true.

Multithread Debugging

Set the breakpoint’s suspend policy to “Thread” so that only the selected thread pauses. Then choose the desired thread in the Frames view to continue debugging that specific thread.

Code example

关注我
们,
设为星标,每天7:30不见不散,架构路上与您共享
回复"
架构师
"获取资源