How To Check IsNumber In Java?

Use `Double.parseDouble(str)` inside a `try-catch`

Use `Integer.parseInt(str)` for integer-only checks

Use `Long.parseLong(str)` for long integer checks

Use `Pattern.matches(“-?\d+(\.\d+)?”, str)` for a simple numeric regex check

Use `str.matches(“-?\d+(\.\d+)?”)` for a simple numeric regex check

Use `NumberUtils.isCreatable(str)` from Apache Commons Lang

Use `NumberUtils.isParsable(str)` from Apache Commons Lang

Use `Scanner` with `hasNextDouble()` or `hasNextInt()`

Use `Character.isDigit(ch)` for single-character digit checks

Use `BigDecimal` constructor in a `try-catch` for decimal number validation