How to get the first date and last date of the previous month? (Java)

With Calendar

Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, -1);
cal.set(Calendar.DATE, 1);
Date firstDateOfPreviousMonth = cal.getTime();

cal.set(Calendar.DATE, cal.getActualMaximum(Calendar.DATE)); // changed calendar to cal

Date lastDateOfPreviousMonth = cal.getTime();

See

ideone demo

tl;dr

YearMonth.now().minusMonths( 1 ).atDay( 1 )

…and…

YearMonth.now().minusMonths( 1 ).atEndOfMonth()

Avoid j.u.Date

Avoid the bundled java.util.Date and .Calendar classes as they are notoriously troublesome. Instead, use the java.time package in Java 8 and later.

java.time

The new java.time framework in Java 8 (Tutorial) has commands for this.

The aptly-named YearMonth class represents a month of a year, without any specific day or time. From there we can ask for the first and last days of the month.

ZoneId zoneId = ZoneId.of( "America/Montreal" );
YearMonth yearMonthNow = YearMonth.now( zoneId );
YearMonth yearMonthPrevious = yearMonthNow.minusMonths( 1 );
LocalDate firstOfMonth = yearMonthPrevious.atDay( 1 );
LocalDate lastOfMonth = yearMonthPrevious.atEndOfMonth();

Joda-Time

UPDATE: The Joda-Time project is now in maintenance mode, with the team advising migration to the java.time classes. See Tutorial by Oracle.

In Joda-Time 2.8, use the LocalDate class if you do not care about time-of-day.

LocalDate today = LocalDate.now( DateTimeZone.forID( "Europe/Paris" ) );
LocalDate firstOfThisMonth = today.withDayOfMonth( 1 );
LocalDate firstOfLastMonth = firstOfThisMonth.minusMonths( 1 );
LocalDate endOfLastMonth = firstOfThisMonth.minusDays( 1 );

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

Java SE 8, Java SE 9, Java SE 10, and later
Built-in.
Part of the standard Java API with a bundled implementation.
Java 9 adds some minor features and fixes.
Java SE 6 and Java SE 7
Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport.
Android
Later versions of Android bundle implementations of the java.time classes.
For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP….

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Use JodaTime

DateMidnight now = new DateMidnight();
DateMidnight beginningOfLastMonth = now.minusMonths(1).withDayOfMonth(1);
DateMidnight endOfLastMonth = now.withDayOfMonth(1).minusDays(1);
System.out.println(beginningOfLastMonth);
System.out.println(endOfLastMonth);

Output:

2012-04-01T00:00:00.000+02:00
2012-04-30T00:00:00.000+02:00

Explanation: a DateMidnight object is a Date Object with no time of day information, which seems like just what you need. If not, replace all occurrences of DateMidnight with DateTime in the above code.

well you could create a calendar object, set the date to the first day of the current month (should be the first :P) and then you can do two operations: from your calendar object you can subtract a particular period of time, e.g. a month (this would give you the first date of the previous month, or a day, which would give you the last day of the previous month. i didn't try it but this would be my first steps.

Would also like to add something to Jigar's answer. Use the DateFormat class to get the date in the format you specified in the question:

DateFormat df = DateFormat.getInstance(DateFormat.SHORT);
System.out.println(df.format(firstDateOfPreviousMonth));
System.out.println(df.format(lastDateOfPreviousMonth));